diff --git a/Misc/NEWS.d/next/Library/2024-06-06-17-49-07.gh-issue-120170.DUxhmT.rst b/Misc/NEWS.d/next/Library/2024-06-06-17-49-07.gh-issue-120170.DUxhmT.rst
new file mode 100644
index 00000000000000..ce7d874aa20375
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-06-06-17-49-07.gh-issue-120170.DUxhmT.rst
@@ -0,0 +1,3 @@
+Fix an issue in the :mod:`!_pickle` extension module in which importing
+:mod:`multiprocessing` could change how pickle identifies which module an
+object belongs to, potentially breaking the unpickling of those objects.
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 5641f93391c551..a458f5d8141227 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -1870,6 +1870,10 @@ _checkmodule(PyObject *module_name, PyObject *module,
             _PyUnicode_EqualToASCIIString(module_name, "__main__")) {
         return -1;
     }
+    if (PyUnicode_Check(module_name) &&
+            _PyUnicode_EqualToASCIIString(module_name, "__mp_main__")) {
+        return -1;
+    }
 
     PyObject *candidate = getattribute(module, dotted_path, 0);
     if (candidate == NULL) {