diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index 6b45e077b48..66a1e2a171f 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -539,7 +539,11 @@ def __init__(self, request, tmpdir_factory):
 
         # Environment (updates) for inner runs.
         tmphome = str(self.tmpdir)
-        self._env_run_update = {"HOME": tmphome, "USERPROFILE": tmphome}
+        self._env_run_update = {
+            "HOME": tmphome,
+            "USERPROFILE": tmphome,
+            "PYTEST_DISABLE_PLUGIN_AUTOLOAD": "1",
+        }
 
     def __repr__(self):
         return "<Testdir {!r}>".format(self.tmpdir)
diff --git a/testing/acceptance_test.py b/testing/acceptance_test.py
index 578ab45eb03..084cc8245a0 100644
--- a/testing/acceptance_test.py
+++ b/testing/acceptance_test.py
@@ -104,6 +104,8 @@ def test_option(pytestconfig):
 
     @pytest.mark.parametrize("load_cov_early", [True, False])
     def test_early_load_setuptools_name(self, testdir, monkeypatch, load_cov_early):
+        del testdir._env_run_update["PYTEST_DISABLE_PLUGIN_AUTOLOAD"]
+
         testdir.makepyfile(mytestplugin1_module="")
         testdir.makepyfile(mytestplugin2_module="")
         testdir.makepyfile(mycov_module="")
diff --git a/testing/test_helpconfig.py b/testing/test_helpconfig.py
index 962750f7b3a..c945a5cc2d6 100644
--- a/testing/test_helpconfig.py
+++ b/testing/test_helpconfig.py
@@ -3,6 +3,7 @@
 
 
 def test_version(testdir, pytestconfig):
+    del testdir._env_run_update["PYTEST_DISABLE_PLUGIN_AUTOLOAD"]
     result = testdir.runpytest("--version")
     assert result.ret == 0
     # p = py.path.local(py.__file__).dirpath()
diff --git a/testing/test_junitxml.py b/testing/test_junitxml.py
index 885d259415b..73d2ef49efe 100644
--- a/testing/test_junitxml.py
+++ b/testing/test_junitxml.py
@@ -1226,6 +1226,7 @@ def test_pass():
 
 def test_runs_twice_xdist(testdir, run_and_parse):
     pytest.importorskip("xdist")
+    del testdir._env_run_update["PYTEST_DISABLE_PLUGIN_AUTOLOAD"]
     f = testdir.makepyfile(
         """
         def test_pass():
diff --git a/testing/test_terminal.py b/testing/test_terminal.py
index 1bec577b865..50ea773af22 100644
--- a/testing/test_terminal.py
+++ b/testing/test_terminal.py
@@ -595,6 +595,7 @@ def test_method(self):
         assert result.ret == 0
 
     def test_header_trailer_info(self, testdir, request):
+        del testdir._env_run_update["PYTEST_DISABLE_PLUGIN_AUTOLOAD"]
         testdir.makepyfile(
             """
             def test_passes():
@@ -705,6 +706,7 @@ def test_verbose_reporting_xdist(self, verbose_testfile, testdir, pytestconfig):
         if not pytestconfig.pluginmanager.get_plugin("xdist"):
             pytest.skip("xdist plugin not installed")
 
+        del testdir._env_run_update["PYTEST_DISABLE_PLUGIN_AUTOLOAD"]
         result = testdir.runpytest(
             verbose_testfile, "-v", "-n 1", "-Walways::pytest.PytestWarning"
         )