diff --git a/Lib/test/test_tcl.py b/Lib/test/test_tcl.py
index 1d90ac10ad77ad..31ef1457ef3944 100644
--- a/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@ -595,6 +595,11 @@ def test_returning_deeply_nested(self):
         interp.eval('set x a; for {set i 0} {$i < %d} {incr i} {set x [list $x]}'
                     % support.exceeds_recursion_limit())
         self.assertRaises(RecursionError, interp.getvar, 'x')
+        interp = None
+
+        # gh-161353: Clean up explicitly per-thread state to avoid leaking an
+        # event handle on Windows when test_tcl is run with -R 3:3 option.
+        _tkinter._finalize_thread()
 
     def test_user_command(self):
         result = None
diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 9a09687e55b981..9540839b9682bc 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -3584,6 +3584,20 @@ _tkinter_getbusywaitinterval_impl(PyObject *module)
     return Tkinter_busywaitinterval;
 }
 
+/*[clinic input]
+_tkinter._finalize_thread
+
+Clean up per-thread state.
+[clinic start generated code]*/
+
+static PyObject *
+_tkinter__finalize_thread_impl(PyObject *module)
+/*[clinic end generated code: output=4ed0d3be4d1f8de8 input=ea68096ee9b83d23]*/
+{
+    Tcl_FinalizeThread();
+    Py_RETURN_NONE;
+}
+
 #include "clinic/_tkinter.c.h"
 
 static PyMethodDef Tktt_methods[] =
@@ -3681,6 +3695,7 @@ static PyMethodDef moduleMethods[] =
     _TKINTER_CREATE_METHODDEF
     _TKINTER_SETBUSYWAITINTERVAL_METHODDEF
     _TKINTER_GETBUSYWAITINTERVAL_METHODDEF
+    _TKINTER__FINALIZE_THREAD_METHODDEF
     {NULL,                 NULL}
 };
 
diff --git a/Modules/clinic/_tkinter.c.h b/Modules/clinic/_tkinter.c.h
index 1e197167409a03..22529aaf7bee44 100644
--- a/Modules/clinic/_tkinter.c.h
+++ b/Modules/clinic/_tkinter.c.h
@@ -956,6 +956,24 @@ _tkinter_getbusywaitinterval(PyObject *module, PyObject *Py_UNUSED(ignored))
     return return_value;
 }
 
+PyDoc_STRVAR(_tkinter__finalize_thread__doc__,
+"_finalize_thread($module, /)\n"
+"--\n"
+"\n"
+"Clean up per-thread state.");
+
+#define _TKINTER__FINALIZE_THREAD_METHODDEF    \
+    {"_finalize_thread", (PyCFunction)_tkinter__finalize_thread, METH_NOARGS, _tkinter__finalize_thread__doc__},
+
+static PyObject *
+_tkinter__finalize_thread_impl(PyObject *module);
+
+static PyObject *
+_tkinter__finalize_thread(PyObject *module, PyObject *Py_UNUSED(ignored))
+{
+    return _tkinter__finalize_thread_impl(module);
+}
+
 #ifndef _TKINTER_TKAPP_CREATEFILEHANDLER_METHODDEF
     #define _TKINTER_TKAPP_CREATEFILEHANDLER_METHODDEF
 #endif /* !defined(_TKINTER_TKAPP_CREATEFILEHANDLER_METHODDEF) */
@@ -963,4 +981,4 @@ _tkinter_getbusywaitinterval(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef _TKINTER_TKAPP_DELETEFILEHANDLER_METHODDEF
     #define _TKINTER_TKAPP_DELETEFILEHANDLER_METHODDEF
 #endif /* !defined(_TKINTER_TKAPP_DELETEFILEHANDLER_METHODDEF) */
-/*[clinic end generated code: output=229ae8ed00ee4e40 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c94e363a6f9de67d input=a9049054013a1b77]*/