diff --git a/docs/changelog/425.feature.rst b/docs/changelog/425.feature.rst
new file mode 100644
index 000000000..aed60e75d
--- /dev/null
+++ b/docs/changelog/425.feature.rst
@@ -0,0 +1,2 @@
+Added support for Tcl and Tkinter. You're welcome.
+Contributed by :user:`esafak`.
diff --git a/src/virtualenv/activation/bash/activate.sh b/src/virtualenv/activation/bash/activate.sh
index d3cf34784..4ffeb8257 100644
--- a/src/virtualenv/activation/bash/activate.sh
+++ b/src/virtualenv/activation/bash/activate.sh
@@ -23,6 +23,17 @@ deactivate () {
         unset _OLD_VIRTUAL_PYTHONHOME
     fi
 
+    if ! [ -z "${_OLD_VIRTUAL_TCL_LIBRARY+_}" ]; then
+        TCL_LIBRARY="$_OLD_VIRTUAL_TCL_LIBRARY"
+        export TCL_LIBRARY
+        unset _OLD_VIRTUAL_TCL_LIBRARY
+    fi
+    if ! [ -z "${_OLD_VIRTUAL_TK_LIBRARY+_}" ]; then
+        TK_LIBRARY="$_OLD_VIRTUAL_TK_LIBRARY"
+        export TK_LIBRARY
+        unset _OLD_VIRTUAL_TK_LIBRARY
+    fi
+
     # The hash command must be called to get it to forget past
     # commands. Without forgetting past commands the $PATH changes
     # we made may not be respected
@@ -68,6 +79,22 @@ if ! [ -z "${PYTHONHOME+_}" ] ; then
     unset PYTHONHOME
 fi
 
+if [ __TCL_LIBRARY__ != "''" ]; then
+    if ! [ -z "${TCL_LIBRARY+_}" ] ; then
+        _OLD_VIRTUAL_TCL_LIBRARY="$TCL_LIBRARY"
+    fi
+    TCL_LIBRARY=__TCL_LIBRARY__
+    export TCL_LIBRARY
+fi
+
+if [ __TK_LIBRARY__ != "''" ]; then
+    if ! [ -z "${TK_LIBRARY+_}" ] ; then
+        _OLD_VIRTUAL_TK_LIBRARY="$TK_LIBRARY"
+    fi
+    TK_LIBRARY=__TK_LIBRARY__
+    export TK_LIBRARY
+fi
+
 if [ -z "${VIRTUAL_ENV_DISABLE_PROMPT-}" ] ; then
     _OLD_VIRTUAL_PS1="${PS1-}"
     PS1="(${VIRTUAL_ENV_PROMPT}) ${PS1-}"
diff --git a/src/virtualenv/activation/batch/activate.bat b/src/virtualenv/activation/batch/activate.bat
index 36b0a8bd7..62f393c80 100644
--- a/src/virtualenv/activation/batch/activate.bat
+++ b/src/virtualenv/activation/batch/activate.bat
@@ -33,6 +33,12 @@
 
 @set PYTHONHOME=
 
+@if defined TCL_LIBRARY @set "_OLD_VIRTUAL_TCL_LIBRARY=%TCL_LIBRARY%"
+@if NOT "__TCL_LIBRARY__"=="" @set "TCL_LIBRARY=__TCL_LIBRARY__"
+
+@if defined TK_LIBRARY @set "_OLD_VIRTUAL_TK_LIBRARY=%TK_LIBRARY%"
+@if NOT "__TK_LIBRARY__"=="" @set "TK_LIBRARY=__TK_LIBRARY__"
+
 @REM if defined _OLD_VIRTUAL_PATH (
 @if not defined _OLD_VIRTUAL_PATH @goto ENDIFVPATH1
     @set "PATH=%_OLD_VIRTUAL_PATH%"
diff --git a/src/virtualenv/activation/batch/deactivate.bat b/src/virtualenv/activation/batch/deactivate.bat
index 8939c6c0d..7a12d47ed 100644
--- a/src/virtualenv/activation/batch/deactivate.bat
+++ b/src/virtualenv/activation/batch/deactivate.bat
@@ -12,6 +12,14 @@
     @set _OLD_VIRTUAL_PYTHONHOME=
 :ENDIFVHOME
 
+@if defined _OLD_VIRTUAL_TCL_LIBRARY @set "TCL_LIBRARY=%_OLD_VIRTUAL_TCL_LIBRARY%"
+@if not defined _OLD_VIRTUAL_TCL_LIBRARY @set TCL_LIBRARY=
+@set _OLD_VIRTUAL_TCL_LIBRARY=
+
+@if defined _OLD_VIRTUAL_TK_LIBRARY @set "TK_LIBRARY=%_OLD_VIRTUAL_TK_LIBRARY%"
+@if not defined _OLD_VIRTUAL_TK_LIBRARY @set TK_LIBRARY=
+@set _OLD_VIRTUAL_TK_LIBRARY=
+
 @if not defined _OLD_VIRTUAL_PATH @goto ENDIFVPATH
     @set "PATH=%_OLD_VIRTUAL_PATH%"
     @set _OLD_VIRTUAL_PATH=
diff --git a/src/virtualenv/activation/cshell/activate.csh b/src/virtualenv/activation/cshell/activate.csh
index 24de5508b..5c02616d7 100644
--- a/src/virtualenv/activation/cshell/activate.csh
+++ b/src/virtualenv/activation/cshell/activate.csh
@@ -5,7 +5,7 @@
 set newline='\
 '
 
-alias deactivate 'test $?_OLD_VIRTUAL_PATH != 0 && setenv PATH "$_OLD_VIRTUAL_PATH:q" && unset _OLD_VIRTUAL_PATH; rehash; test $?_OLD_VIRTUAL_PROMPT != 0 && set prompt="$_OLD_VIRTUAL_PROMPT:q" && unset _OLD_VIRTUAL_PROMPT; unsetenv VIRTUAL_ENV; unsetenv VIRTUAL_ENV_PROMPT; test "\!:*" != "nondestructive" && unalias deactivate && unalias pydoc'
+alias deactivate 'test $?_OLD_VIRTUAL_PATH != 0 && setenv PATH "$_OLD_VIRTUAL_PATH:q" && unset _OLD_VIRTUAL_PATH; rehash; test $?_OLD_VIRTUAL_TCL_LIBRARY != 0 && setenv TCL_LIBRARY "$_OLD_VIRTUAL_TCL_LIBRARY:q" && unset _OLD_VIRTUAL_TCL_LIBRARY || unsetenv TCL_LIBRARY; test $?_OLD_VIRTUAL_TK_LIBRARY != 0 && setenv TK_LIBRARY "$_OLD_VIRTUAL_TK_LIBRARY:q" && unset _OLD_VIRTUAL_TK_LIBRARY || unsetenv TK_LIBRARY; test $?_OLD_VIRTUAL_PROMPT != 0 && set prompt="$_OLD_VIRTUAL_PROMPT:q" && unset _OLD_VIRTUAL_PROMPT; unsetenv VIRTUAL_ENV; unsetenv VIRTUAL_ENV_PROMPT; test "\!:*" != "nondestructive" && unalias deactivate && unalias pydoc'
 
 # Unset irrelevant variables.
 deactivate nondestructive
@@ -15,7 +15,19 @@ setenv VIRTUAL_ENV __VIRTUAL_ENV__
 set _OLD_VIRTUAL_PATH="$PATH:q"
 setenv PATH "$VIRTUAL_ENV:q/"__BIN_NAME__":$PATH:q"
 
+if (__TCL_LIBRARY__ != "") then
+    if ($?TCL_LIBRARY) then
+        set _OLD_VIRTUAL_TCL_LIBRARY="$TCL_LIBRARY"
+    endif
+    setenv TCL_LIBRARY __TCL_LIBRARY__
+endif
 
+if (__TK_LIBRARY__ != "") then
+    if ($?TK_LIBRARY) then
+        set _OLD_VIRTUAL_TK_LIBRARY="$TK_LIBRARY"
+    endif
+    setenv TK_LIBRARY __TK_LIBRARY__
+endif
 
 if (__VIRTUAL_PROMPT__ != "") then
     setenv VIRTUAL_ENV_PROMPT __VIRTUAL_PROMPT__
diff --git a/src/virtualenv/activation/fish/__init__.py b/src/virtualenv/activation/fish/__init__.py
index 57f790f47..28052e64f 100644
--- a/src/virtualenv/activation/fish/__init__.py
+++ b/src/virtualenv/activation/fish/__init__.py
@@ -7,6 +7,14 @@ class FishActivator(ViaTemplateActivator):
     def templates(self):
         yield "activate.fish"
 
+    def replacements(self, creator, dest):
+        data = super().replacements(creator, dest)
+        data.update({
+            "__TCL_LIBRARY__": creator.interpreter.tcl_lib or "",
+            "__TK_LIBRARY__": creator.interpreter.tk_lib or "",
+        })
+        return data
+
 
 __all__ = [
     "FishActivator",
diff --git a/src/virtualenv/activation/fish/activate.fish b/src/virtualenv/activation/fish/activate.fish
index 518bc4cff..c9d174997 100644
--- a/src/virtualenv/activation/fish/activate.fish
+++ b/src/virtualenv/activation/fish/activate.fish
@@ -26,6 +26,23 @@ function deactivate -d 'Exit virtualenv mode and return to the normal environmen
         set -e _OLD_VIRTUAL_PATH
     end
 
+    if test -n __TCL_LIBRARY__
+      if test -n "$_OLD_VIRTUAL_TCL_LIBRARY";
+        set -gx TCL_LIBRARY "$_OLD_VIRTUAL_TCL_LIBRARY";
+        set -e _OLD_VIRTUAL_TCL_LIBRARY;
+      else;
+        set -e TCL_LIBRARY;
+      end
+    end
+    if test -n __TK_LIBRARY__
+      if test -n "$_OLD_VIRTUAL_TK_LIBRARY";
+        set -gx TK_LIBRARY "$_OLD_VIRTUAL_TK_LIBRARY";
+        set -e _OLD_VIRTUAL_TK_LIBRARY;
+      else;
+        set -e TK_LIBRARY;
+      end
+    end
+
     if test -n "$_OLD_VIRTUAL_PYTHONHOME"
         set -gx PYTHONHOME "$_OLD_VIRTUAL_PYTHONHOME"
         set -e _OLD_VIRTUAL_PYTHONHOME
@@ -68,6 +85,19 @@ else
 end
 set -gx PATH "$VIRTUAL_ENV"'/'__BIN_NAME__ $PATH
 
+if test -n __TCL_LIBRARY__
+  if set -q TCL_LIBRARY;
+    set -gx _OLD_VIRTUAL_TCL_LIBRARY $TCL_LIBRARY;
+  end
+  set -gx TCL_LIBRARY '__TCL_LIBRARY__'
+end
+if test -n __TK_LIBRARY__
+  if set -q TK_LIBRARY;
+    set -gx _OLD_VIRTUAL_TK_LIBRARY $TK_LIBRARY;
+  end
+  set -gx TK_LIBRARY '__TK_LIBRARY__'
+end
+
 # Prompt override provided?
 # If not, just use the environment name.
 if test -n __VIRTUAL_PROMPT__
diff --git a/src/virtualenv/activation/nushell/__init__.py b/src/virtualenv/activation/nushell/__init__.py
index ef7a79a9c..9558a70a5 100644
--- a/src/virtualenv/activation/nushell/__init__.py
+++ b/src/virtualenv/activation/nushell/__init__.py
@@ -12,6 +12,8 @@ def quote(string):
         """
         Nushell supports raw strings like: r###'this is a string'###.
 
+        https://github.com/nushell/nushell.github.io/blob/main/book/working_with_strings.md
+
         This method finds the maximum continuous sharps in the string and then
         quote it with an extra sharp.
         """
@@ -32,6 +34,8 @@ def replacements(self, creator, dest_folder):  # noqa: ARG002
             "__VIRTUAL_ENV__": str(creator.dest),
             "__VIRTUAL_NAME__": creator.env_name,
             "__BIN_NAME__": str(creator.bin_dir.relative_to(creator.dest)),
+            "__TCL_LIBRARY__": creator.interpreter.tcl_lib or "",
+            "__TK_LIBRARY__": creator.interpreter.tk_lib or "",
         }
 
 
diff --git a/src/virtualenv/activation/nushell/activate.nu b/src/virtualenv/activation/nushell/activate.nu
index 7f43071f7..b48fdd03f 100644
--- a/src/virtualenv/activation/nushell/activate.nu
+++ b/src/virtualenv/activation/nushell/activate.nu
@@ -58,6 +58,12 @@ export-env {
         __VIRTUAL_PROMPT__
     }
     let new_env = { $path_name: $new_path VIRTUAL_ENV: $virtual_env VIRTUAL_ENV_PROMPT: $virtual_env_prompt }
+    if (has-env 'TCL_LIBRARY')  {
+        let $new_env = $new_env | insert TCL_LIBRARY __TCL_LIBRARY__
+    }
+    if (has-env 'TK_LIBRARY')  {
+        let $new_env = $new_env | insert TK_LIBRARY __TK_LIBRARY__
+    }
     let old_prompt_command = if (has-env 'PROMPT_COMMAND') { $env.PROMPT_COMMAND } else { '' }
     let new_env = if (is-env-true 'VIRTUAL_ENV_DISABLE_PROMPT') {
         $new_env
diff --git a/src/virtualenv/activation/powershell/activate.ps1 b/src/virtualenv/activation/powershell/activate.ps1
index bd30e2eed..9f95e4370 100644
--- a/src/virtualenv/activation/powershell/activate.ps1
+++ b/src/virtualenv/activation/powershell/activate.ps1
@@ -7,6 +7,24 @@ function global:deactivate([switch] $NonDestructive) {
         Remove-Variable "_OLD_VIRTUAL_PATH" -Scope global
     }
 
+    if (Test-Path variable:_OLD_VIRTUAL_TCL_LIBRARY) {
+        $env:TCL_LIBRARY = $variable:_OLD_VIRTUAL_TCL_LIBRARY
+        Remove-Variable "_OLD_VIRTUAL_TCL_LIBRARY" -Scope global
+    } else {
+        if (Test-Path env:TCL_LIBRARY) {
+            Remove-Item env:TCL_LIBRARY -ErrorAction SilentlyContinue
+        }
+    }
+
+    if (Test-Path variable:_OLD_VIRTUAL_TK_LIBRARY) {
+        $env:TK_LIBRARY = $variable:_OLD_VIRTUAL_TK_LIBRARY
+        Remove-Variable "_OLD_VIRTUAL_TK_LIBRARY" -Scope global
+    } else {
+        if (Test-Path env:TK_LIBRARY) {
+            Remove-Item env:TK_LIBRARY -ErrorAction SilentlyContinue
+        }
+    }
+
     if (Test-Path function:_old_virtual_prompt) {
         $function:prompt = $function:_old_virtual_prompt
         Remove-Item function:\_old_virtual_prompt
@@ -44,6 +62,20 @@ else {
     $env:VIRTUAL_ENV_PROMPT = $( Split-Path $env:VIRTUAL_ENV -Leaf )
 }
 
+if (__TCL_LIBRARY__ -ne "") {
+    if (Test-Path env:TCL_LIBRARY) {
+        New-Variable -Scope global -Name _OLD_VIRTUAL_TCL_LIBRARY -Value $env:TCL_LIBRARY
+    }
+    $env:TCL_LIBRARY = __TCL_LIBRARY__
+}
+
+if (__TK_LIBRARY__ -ne "") {
+    if (Test-Path env:TK_LIBRARY) {
+        New-Variable -Scope global -Name _OLD_VIRTUAL_TK_LIBRARY -Value $env:TK_LIBRARY
+    }
+    $env:TK_LIBRARY = __TK_LIBRARY__
+}
+
 New-Variable -Scope global -Name _OLD_VIRTUAL_PATH -Value $env:PATH
 
 $env:PATH = "$env:VIRTUAL_ENV/" + __BIN_NAME__ + __PATH_SEP__ + $env:PATH
diff --git a/src/virtualenv/activation/via_template.py b/src/virtualenv/activation/via_template.py
index 6fa4474d2..83229441a 100644
--- a/src/virtualenv/activation/via_template.py
+++ b/src/virtualenv/activation/via_template.py
@@ -47,6 +47,8 @@ def replacements(self, creator, dest_folder):  # noqa: ARG002
             "__VIRTUAL_NAME__": creator.env_name,
             "__BIN_NAME__": str(creator.bin_dir.relative_to(creator.dest)),
             "__PATH_SEP__": os.pathsep,
+            "__TCL_LIBRARY__": creator.interpreter.tcl_lib or "",
+            "__TK_LIBRARY__": creator.interpreter.tk_lib or "",
         }
 
     def _generate(self, replacements, templates, to_folder, creator):
diff --git a/src/virtualenv/discovery/py_info.py b/src/virtualenv/discovery/py_info.py
index 6f2575a76..ed9962034 100644
--- a/src/virtualenv/discovery/py_info.py
+++ b/src/virtualenv/discovery/py_info.py
@@ -123,6 +123,8 @@ def abs_path(v):
 
         self.sysconfig_vars = {i: sysconfig.get_config_var(i or "") for i in config_var_keys}
 
+        self.tcl_lib, self.tk_lib = self._get_tcl_tk_libs() if "TCL_LIBRARY" in os.environ else None, None
+
         confs = {
             k: (self.system_prefix if v is not None and v.startswith(self.prefix) else v)
             for k, v in self.sysconfig_vars.items()
@@ -132,6 +134,59 @@ def abs_path(v):
         self.max_size = getattr(sys, "maxsize", getattr(sys, "maxint", None))
         self._creators = None
 
+    @staticmethod
+    def _get_tcl_tk_libs():
+        """
+        Detects the tcl and tk libraries using tkinter.
+
+        This works reliably but spins up tkinter, which is heavy if you don't need it.
+        """
+        tcl_lib, tk_lib = None, None
+        try:
+            import tkinter as tk  # noqa: PLC0415
+        except ImportError:
+            pass
+        else:
+            try:
+                tcl = tk.Tcl()
+                tcl_lib = tcl.eval("info library")
+
+                # Try to get TK library path directly first
+                try:
+                    tk_lib = tcl.eval("set tk_library")
+                    if tk_lib and os.path.isdir(tk_lib):
+                        pass  # We found it directly
+                    else:
+                        tk_lib = None  # Reset if invalid
+                except tk.TclError:
+                    tk_lib = None
+
+                # If direct query failed, try constructing the path
+                if tk_lib is None:
+                    tk_version = tcl.eval("package require Tk")
+                    tcl_parent = os.path.dirname(tcl_lib)
+
+                    # Try different version formats
+                    version_variants = [
+                        tk_version,  # Full version like "8.6.12"
+                        ".".join(tk_version.split(".")[:2]),  # Major.minor like "8.6"
+                        tk_version.split(".")[0],  # Just major like "8"
+                    ]
+
+                    for version in version_variants:
+                        tk_lib_path = os.path.join(tcl_parent, f"tk{version}")
+                        if not os.path.isdir(tk_lib_path):
+                            continue
+                        # Validate it's actually a TK directory
+                        if os.path.exists(os.path.join(tk_lib_path, "tk.tcl")):
+                            tk_lib = tk_lib_path
+                            break
+
+            except tk.TclError:
+                pass
+
+        return tcl_lib, tk_lib
+
     def _fast_get_system_executable(self):
         """Try to get the system executable by just looking at properties."""
         if self.real_prefix or (  # noqa: PLR1702
diff --git a/tests/unit/activation/conftest.py b/tests/unit/activation/conftest.py
index 1c945436d..53a819f96 100644
--- a/tests/unit/activation/conftest.py
+++ b/tests/unit/activation/conftest.py
@@ -130,13 +130,13 @@ def _get_test_lines(self, activate_script):
         ]
 
     def assert_output(self, out, raw, tmp_path):
-        # pre-activation
+        """Compare _get_test_lines() with the expected values."""
         assert out[0], raw
         assert out[1] == "None", raw
         assert out[2] == "None", raw
-        # post-activation
-        expected = self._creator.exe.parent / os.path.basename(sys.executable)
-        assert self.norm_path(out[3]) == self.norm_path(expected), raw
+        # self.activate_call(activate_script) runs at this point
+        python_exe = self._creator.exe.parent / os.path.basename(sys.executable)
+        assert self.norm_path(out[3]) == self.norm_path(python_exe), raw
         assert self.norm_path(out[4]) == self.norm_path(self._creator.dest).replace("\\\\", "\\"), raw
         assert out[5] == self._creator.env_name
         # Some attempts to test the prompt output print more than 1 line.
@@ -232,6 +232,7 @@ def raise_on_non_source_class():
 def activation_python(request, tmp_path_factory, special_char_name, current_fastest):
     dest = os.path.join(str(tmp_path_factory.mktemp("activation-tester-env")), special_char_name)
     cmd = ["--without-pip", dest, "--creator", current_fastest, "-vv", "--no-periodic-update"]
+    # `params` is accessed here. https://docs.pytest.org/en/stable/reference/reference.html#pytest-fixture
     if request.param:
         cmd += ["--prompt", special_char_name]
     session = cli_run(cmd)
diff --git a/tests/unit/activation/test_bash.py b/tests/unit/activation/test_bash.py
index d89f1606a..4ebe5c063 100644
--- a/tests/unit/activation/test_bash.py
+++ b/tests/unit/activation/test_bash.py
@@ -1,11 +1,68 @@
 from __future__ import annotations
 
+from argparse import Namespace
+
 import pytest
 
 from virtualenv.activation import BashActivator
 from virtualenv.info import IS_WIN
 
 
+@pytest.mark.skipif(IS_WIN, reason="Github Actions ships with WSL bash")
+@pytest.mark.parametrize(
+    ("tcl_lib", "tk_lib", "present"),
+    [
+        ("/path/to/tcl", "/path/to/tk", True),
+        (None, None, False),
+    ],
+)
+def test_bash_tkinter_generation(tmp_path, tcl_lib, tk_lib, present):
+    # GIVEN
+    class MockInterpreter:
+        pass
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = tcl_lib
+    interpreter.tk_lib = tk_lib
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = BashActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    content = (creator.bin_dir / "activate").read_text(encoding="utf-8")
+
+    # THEN
+    # The teardown logic is always present in deactivate()
+    assert "unset _OLD_VIRTUAL_TCL_LIBRARY" in content
+    assert "unset _OLD_VIRTUAL_TK_LIBRARY" in content
+
+    if present:
+        assert "if [ /path/to/tcl != \"''\" ]; then" in content
+        assert "TCL_LIBRARY=/path/to/tcl" in content
+        assert "export TCL_LIBRARY" in content
+
+        assert "if [ /path/to/tk != \"''\" ]; then" in content
+        assert "TK_LIBRARY=/path/to/tk" in content
+        assert "export TK_LIBRARY" in content
+    else:
+        # When not present, the if condition is false, so the block is not executed
+        assert "if [ '' != \"''\" ]; then" in content
+        assert "TCL_LIBRARY=''" in content
+        # The export is inside the if, so this is fine
+        assert "export TCL_LIBRARY" in content
+
+
 @pytest.mark.skipif(IS_WIN, reason="Github Actions ships with WSL bash")
 @pytest.mark.parametrize("hashing_enabled", [True, False])
 def test_bash(raise_on_non_source_class, hashing_enabled, activation_tester):
diff --git a/tests/unit/activation/test_batch.py b/tests/unit/activation/test_batch.py
index 13d84442e..db2595860 100644
--- a/tests/unit/activation/test_batch.py
+++ b/tests/unit/activation/test_batch.py
@@ -1,10 +1,57 @@
 from __future__ import annotations
 
+from argparse import Namespace
+
 import pytest
 
 from virtualenv.activation import BatchActivator
 
 
+@pytest.mark.parametrize(
+    ("tcl_lib", "tk_lib", "present"),
+    [
+        ("C:\\tcl", "C:\\tk", True),
+        (None, None, False),
+    ],
+)
+def test_batch_tkinter_generation(tmp_path, tcl_lib, tk_lib, present):
+    # GIVEN
+    class MockInterpreter:
+        os = "nt"
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = tcl_lib
+    interpreter.tk_lib = tk_lib
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = BatchActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    activate_content = (creator.bin_dir / "activate.bat").read_text(encoding="utf-8")
+    deactivate_content = (creator.bin_dir / "deactivate.bat").read_text(encoding="utf-8")
+
+    # THEN
+    if present:
+        assert '@if NOT "C:\\tcl"=="" @set "TCL_LIBRARY=C:\\tcl"' in activate_content
+        assert '@if NOT "C:\\tk"=="" @set "TK_LIBRARY=C:\\tk"' in activate_content
+        assert "if defined _OLD_VIRTUAL_TCL_LIBRARY" in deactivate_content
+        assert "if defined _OLD_VIRTUAL_TK_LIBRARY" in deactivate_content
+    else:
+        assert '@if NOT ""=="" @set "TCL_LIBRARY="' in activate_content
+        assert '@if NOT ""=="" @set "TK_LIBRARY="' in activate_content
+
+
 @pytest.mark.usefixtures("activation_python")
 def test_batch(activation_tester_class, activation_tester, tmp_path):
     version_script = tmp_path / "version.bat"
diff --git a/tests/unit/activation/test_csh.py b/tests/unit/activation/test_csh.py
index 125ba42d4..5cea684ec 100644
--- a/tests/unit/activation/test_csh.py
+++ b/tests/unit/activation/test_csh.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import sys
+from argparse import Namespace
 from shutil import which
 from subprocess import check_output
 
@@ -10,6 +11,48 @@
 from virtualenv.activation import CShellActivator
 
 
+@pytest.mark.parametrize(
+    ("tcl_lib", "tk_lib", "present"),
+    [
+        ("/path/to/tcl", "/path/to/tk", True),
+        (None, None, False),
+    ],
+)
+def test_cshell_tkinter_generation(tmp_path, tcl_lib, tk_lib, present):
+    # GIVEN
+    class MockInterpreter:
+        pass
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = tcl_lib
+    interpreter.tk_lib = tk_lib
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = CShellActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    content = (creator.bin_dir / "activate.csh").read_text(encoding="utf-8")
+
+    if present:
+        assert "test $?_OLD_VIRTUAL_TCL_LIBRARY != 0" in content
+        assert "test $?_OLD_VIRTUAL_TK_LIBRARY != 0" in content
+        assert "setenv TCL_LIBRARY /path/to/tcl" in content
+        assert "setenv TK_LIBRARY /path/to/tk" in content
+    else:
+        assert "setenv TCL_LIBRARY ''" in content
+
+
 def test_csh(activation_tester_class, activation_tester):
     exe = f"tcsh{'.exe' if sys.platform == 'win32' else ''}"
     if which(exe):
diff --git a/tests/unit/activation/test_fish.py b/tests/unit/activation/test_fish.py
index 0f3bee25f..c15a8f513 100644
--- a/tests/unit/activation/test_fish.py
+++ b/tests/unit/activation/test_fish.py
@@ -2,6 +2,7 @@
 
 import os
 import sys
+from argparse import Namespace
 
 import pytest
 
@@ -9,6 +10,48 @@
 from virtualenv.info import IS_WIN
 
 
+@pytest.mark.parametrize(
+    ("tcl_lib", "tk_lib", "present"),
+    [
+        ("/path/to/tcl", "/path/to/tk", True),
+        (None, None, False),
+    ],
+)
+def test_fish_tkinter_generation(tmp_path, tcl_lib, tk_lib, present):
+    # GIVEN
+    class MockInterpreter:
+        pass
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = tcl_lib
+    interpreter.tk_lib = tk_lib
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = FishActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    content = (creator.bin_dir / "activate.fish").read_text(encoding="utf-8")
+
+    # THEN
+    if present:
+        assert "set -gx TCL_LIBRARY '/path/to/tcl'" in content
+        assert "set -gx TK_LIBRARY '/path/to/tk'" in content
+    else:
+        assert "if test -n ''\n  if set -q TCL_LIBRARY;" in content
+        assert "if test -n ''\n  if set -q TK_LIBRARY;" in content
+
+
 @pytest.mark.skipif(IS_WIN, reason="we have not setup fish in CI yet")
 def test_fish(activation_tester_class, activation_tester, monkeypatch, tmp_path):
     monkeypatch.setenv("HOME", str(tmp_path))
@@ -46,11 +89,11 @@ def _get_test_lines(self, activate_script):
             ]
 
         def assert_output(self, out, raw, _):
-            # pre-activation
+            """Compare _get_test_lines() with the expected values."""
             assert out[0], raw
             assert out[1] == "None", raw
             assert out[2] == "None", raw
-            # post-activation
+            # self.activate_call(activate_script) runs at this point
             expected = self._creator.exe.parent / os.path.basename(sys.executable)
             assert self.norm_path(out[4]) == self.norm_path(expected), raw
             assert self.norm_path(out[5]) == self.norm_path(self._creator.dest).replace("\\\\", "\\"), raw
diff --git a/tests/unit/activation/test_nushell.py b/tests/unit/activation/test_nushell.py
index fbf75e397..08c5cb1a1 100644
--- a/tests/unit/activation/test_nushell.py
+++ b/tests/unit/activation/test_nushell.py
@@ -1,11 +1,48 @@
 from __future__ import annotations
 
+from argparse import Namespace
 from shutil import which
 
 from virtualenv.activation import NushellActivator
 from virtualenv.info import IS_WIN
 
 
+def test_nushell_tkinter_generation(tmp_path):
+    # GIVEN
+    class MockInterpreter:
+        pass
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = "/path/to/tcl"
+    interpreter.tk_lib = "/path/to/tk"
+    quoted_tcl_path = NushellActivator.quote(interpreter.tcl_lib)
+    quoted_tk_path = NushellActivator.quote(interpreter.tk_lib)
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = NushellActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    content = (creator.bin_dir / "activate.nu").read_text(encoding="utf-8")
+
+    # THEN
+    expected_tcl = f"let $new_env = $new_env | insert TCL_LIBRARY {quoted_tcl_path}"
+    expected_tk = f"let $new_env = $new_env | insert TK_LIBRARY {quoted_tk_path}"
+
+    assert expected_tcl in content
+    assert expected_tk in content
+
+
 def test_nushell(activation_tester_class, activation_tester):
     class Nushell(activation_tester_class):
         def __init__(self, session) -> None:
diff --git a/tests/unit/activation/test_powershell.py b/tests/unit/activation/test_powershell.py
index dab5748d7..2a48956cf 100644
--- a/tests/unit/activation/test_powershell.py
+++ b/tests/unit/activation/test_powershell.py
@@ -1,12 +1,59 @@
 from __future__ import annotations
 
 import sys
+from argparse import Namespace
 
 import pytest
 
 from virtualenv.activation import PowerShellActivator
 
 
+@pytest.mark.parametrize(
+    ("tcl_lib", "tk_lib", "present"),
+    [
+        ("C:\\tcl", "C:\\tk", True),
+        (None, None, False),
+    ],
+)
+def test_powershell_tkinter_generation(tmp_path, tcl_lib, tk_lib, present):
+    # GIVEN
+    class MockInterpreter:
+        os = "nt"
+
+    interpreter = MockInterpreter()
+    interpreter.tcl_lib = tcl_lib
+    interpreter.tk_lib = tk_lib
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / "bin"
+            self.bin_dir.mkdir()
+            self.interpreter = interpreter
+            self.pyenv_cfg = {}
+            self.env_name = "my-env"
+
+    creator = MockCreator(tmp_path)
+    options = Namespace(prompt=None)
+    activator = PowerShellActivator(options)
+
+    # WHEN
+    activator.generate(creator)
+    content = (creator.bin_dir / "activate.ps1").read_text(encoding="utf-8-sig")
+
+    # THEN
+    if present:
+        assert "if ('C:\\tcl' -ne \"\")" in content
+        assert "$env:TCL_LIBRARY = 'C:\\tcl'" in content
+        assert "if ('C:\\tk' -ne \"\")" in content
+        assert "$env:TK_LIBRARY = 'C:\\tk'" in content
+        assert "if (Test-Path variable:_OLD_VIRTUAL_TCL_LIBRARY)" in content
+        assert "if (Test-Path variable:_OLD_VIRTUAL_TK_LIBRARY)" in content
+    else:
+        assert "if ('' -ne \"\")" in content
+        assert "$env:TCL_LIBRARY = ''" in content
+
+
 @pytest.mark.slow
 def test_powershell(activation_tester_class, activation_tester, monkeypatch):
     monkeypatch.setenv("TERM", "xterm")