diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-01-20-13-13-33.bpo-39395.-Khif5.rst b/Misc/NEWS.d/next/Core and Builtins/2020-01-20-13-13-33.bpo-39395.-Khif5.rst
new file mode 100644
index 00000000000000..f4f92b6cd766e7
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-01-20-13-13-33.bpo-39395.-Khif5.rst	
@@ -0,0 +1,2 @@
+Environment variables set by :data:`os.environ` and :func:`os.putenv` are now
+cleared at exit. Python manages their memory which is released at exit.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 322c2159812cdd..c278839b9a43c6 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -2101,10 +2101,36 @@ statresult_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     return (PyObject*)result;
 }
 
+
+#ifdef HAVE_UNSETENV
+/* bpo-39395: Clear environment variables set by os.environ and os.putenv()
+   before clearing posix_putenv_garbage dictionary. Python manages the
+   variables memory which is cleared at exit. */
+static void
+posix_unset_envvars(PyObject *posix_putenv_garbage)
+{
+    if (posix_putenv_garbage == NULL) {
+        return;
+    }
+    assert(PyDict_CheckExact(posix_putenv_garbage));
+
+    Py_ssize_t pos = 0;
+    PyObject *key, *value;
+    while (PyDict_Next(posix_putenv_garbage, &pos, &key, &value)) {
+        /* ignore unsetenv() error */
+        unsetenv(PyBytes_AS_STRING(key));
+    }
+}
+#endif
+
+
 static int
 _posix_clear(PyObject *module)
 {
     Py_CLEAR(_posixstate(module)->billion);
+#ifdef HAVE_UNSETENV
+    posix_unset_envvars(_posixstate(module)->posix_putenv_garbage);
+#endif
     Py_CLEAR(_posixstate(module)->posix_putenv_garbage);
     Py_CLEAR(_posixstate(module)->DirEntryType);
     Py_CLEAR(_posixstate(module)->ScandirIteratorType);