diff --git a/src/mono/CMakeLists.txt b/src/mono/CMakeLists.txt
index 4a58182aa9eae6..4f9a1b1d896c58 100644
--- a/src/mono/CMakeLists.txt
+++ b/src/mono/CMakeLists.txt
@@ -496,6 +496,19 @@ else()
   message(FATAL_ERROR "TARGET_ARCH='${TARGET_ARCH}' not supported.")
 endif()
 
+# Default stack size: 2MB for 64-bit, 1MB for 32-bit.
+# Use large (8MB) stack size for s390x/ppc64le due to limited tail call optimization support.
+# On Windows, use 0 to defer to the OS/PE header default.
+if(TARGET_WIN32)
+  set(MONO_DEFAULT_STACKSIZE 0)
+elseif(TARGET_S390X OR TARGET_POWERPC64)
+  set(MONO_DEFAULT_STACKSIZE 8388608)
+elseif(TARGET_SIZEOF_VOID_P EQUAL 4)
+  set(MONO_DEFAULT_STACKSIZE 1048576)
+else()
+  set(MONO_DEFAULT_STACKSIZE 2097152)
+endif()
+
 # arm64 MacCatalyst runtime host or AOT target is more like Apple mobile targets than x64
 if ((HOST_MACCAT AND HOST_ARM64) OR (TARGET_MACCAT AND TARGET_ARM64))
   set(TARGET_APPLE_MOBILE 1)
diff --git a/src/mono/cmake/config.h.in b/src/mono/cmake/config.h.in
index 4fe413349369af..c887a617527d68 100644
--- a/src/mono/cmake/config.h.in
+++ b/src/mono/cmake/config.h.in
@@ -598,6 +598,9 @@
 /* byte order of target */
 #define TARGET_BYTE_ORDER @TARGET_BYTE_ORDER@
 
+/* default stack size for managed threads */
+#define MONO_DEFAULT_STACKSIZE @MONO_DEFAULT_STACKSIZE@
+
 /* wordsize of target */
 #define TARGET_SIZEOF_VOID_P @TARGET_SIZEOF_VOID_P@
 
diff --git a/src/mono/mono/metadata/threads.c b/src/mono/mono/metadata/threads.c
index b0794d1a9f69f7..8641175cfee2b7 100644
--- a/src/mono/mono/metadata/threads.c
+++ b/src/mono/mono/metadata/threads.c
@@ -204,7 +204,7 @@ static MonoThreadAttachCB mono_thread_attach_cb = NULL;
 static MonoThreadCleanupFunc mono_thread_cleanup_fn = NULL;
 
 /* The default stack size for each thread */
-static guint32 default_stacksize = 0;
+static guint32 default_stacksize = ~0;
 
 static void mono_free_static_data (gpointer* static_data);
 static void mono_init_static_data_info (StaticDataInfo *static_data);
@@ -1371,7 +1371,7 @@ create_thread (MonoThread *thread, MonoInternalThread *internal, MonoThreadStart
 	mono_coop_sem_init (&start_info->registered, 0);
 
 	if (flags != MONO_THREAD_CREATE_FLAGS_SMALL_STACK)
-		stack_set_size = stack_size ? stack_size : default_stacksize;
+		stack_set_size = stack_size ? stack_size : mono_threads_get_default_stacksize();
 	else
 		stack_set_size = 0;
 
@@ -1445,6 +1445,21 @@ mono_threads_set_default_stacksize (guint32 stacksize)
 guint32
 mono_threads_get_default_stacksize (void)
 {
+	if (default_stacksize == ~0)
+	{
+		unsigned long stacksize = 0;
+
+		const char *value = g_getenv ("DOTNET_Thread_DefaultStackSize");
+		if (value) {
+			errno = 0;
+			stacksize = strtoul (value, NULL, 16);
+			if (errno != 0 || stacksize >= UINT_MAX)
+				stacksize = 0;
+		}
+
+		default_stacksize = (guint32)stacksize;
+	}
+
 	return default_stacksize;
 }
 
diff --git a/src/mono/mono/utils/mono-threads-posix.c b/src/mono/mono/utils/mono-threads-posix.c
index fa18993907a032..711c2dd3b64553 100644
--- a/src/mono/mono/utils/mono-threads-posix.c
+++ b/src/mono/mono/utils/mono-threads-posix.c
@@ -72,10 +72,10 @@ mono_thread_platform_create_thread (MonoThreadStart thread_fn, gpointer thread_d
 		if (RUNNING_ON_VALGRIND)
 			set_stack_size = 1 << 20;
 		else
-			set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
-#else
-		set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
 #endif
+		{
+			set_stack_size = MONO_DEFAULT_STACKSIZE;
+		}
 	}
 
 #ifdef PTHREAD_STACK_MIN
diff --git a/src/mono/mono/utils/mono-threads-wasm.c b/src/mono/mono/utils/mono-threads-wasm.c
index f43e46c4ffa20a..88ae9557381000 100644
--- a/src/mono/mono/utils/mono-threads-wasm.c
+++ b/src/mono/mono/utils/mono-threads-wasm.c
@@ -225,8 +225,6 @@ mono_thread_platform_create_thread (MonoThreadStart thread_fn, gpointer thread_d
 		g_error ("%s: pthread_attr_init failed, error: \"%s\" (%d)", __func__, g_strerror (res), res);
 
 #if 0
-	gsize set_stack_size;
-
 	if (stack_size)
 		set_stack_size = *stack_size;
 	else
@@ -238,10 +236,10 @@ mono_thread_platform_create_thread (MonoThreadStart thread_fn, gpointer thread_d
 		if (RUNNING_ON_VALGRIND)
 			set_stack_size = 1 << 20;
 		else
-			set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
-#else
-		set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
 #endif
+		{
+			set_stack_size = MONO_DEFAULT_STACKSIZE;
+		}
 	}
 
 #ifdef PTHREAD_STACK_MIN
diff --git a/src/mono/mono/utils/mono-threads-windows.c b/src/mono/mono/utils/mono-threads-windows.c
index 21997a97b624c1..8aeb089b08340b 100644
--- a/src/mono/mono/utils/mono-threads-windows.c
+++ b/src/mono/mono/utils/mono-threads-windows.c
@@ -395,15 +395,12 @@ mono_threads_suspend_get_abort_signal (void)
 
 #if defined (HOST_WIN32)
 
-// Use default stack size on netcore.
-#define MONO_WIN32_DEFAULT_NATIVE_STACK_SIZE 0
-
 gboolean
 mono_thread_platform_create_thread (MonoThreadStart thread_fn, gpointer thread_data, gsize* const stack_size, MonoNativeThreadId *tid)
 {
 	HANDLE result;
 	DWORD thread_id;
-	gsize set_stack_size = MONO_WIN32_DEFAULT_NATIVE_STACK_SIZE;
+	gsize set_stack_size = MONO_DEFAULT_STACKSIZE;
 
 	if (stack_size && *stack_size)
 		set_stack_size = *stack_size;
@@ -450,7 +447,7 @@ mono_native_thread_id_equals (MonoNativeThreadId id1, MonoNativeThreadId id2)
 gboolean
 mono_native_thread_create (MonoNativeThreadId *tid, gpointer func, gpointer arg)
 {
-	return CreateThread (NULL, MONO_WIN32_DEFAULT_NATIVE_STACK_SIZE, (LPTHREAD_START_ROUTINE)func, arg, 0, tid) != NULL;
+	return CreateThread (NULL, MONO_DEFAULT_STACKSIZE, (LPTHREAD_START_ROUTINE)func, arg, 0, tid) != NULL;
 }
 
 gboolean