diff --git a/Include/internal/pycore_interp_structs.h b/Include/internal/pycore_interp_structs.h
index badc97808c6132..409c0b86342b77 100644
--- a/Include/internal/pycore_interp_structs.h
+++ b/Include/internal/pycore_interp_structs.h
@@ -965,6 +965,7 @@ struct _is {
 #  endif
 #endif
 
+    Py_ssize_t owners;
     /* the initial PyInterpreterState.threads.head */
     _PyThreadStateImpl _initial_thread;
     // _initial_thread should be the last field of PyInterpreterState.
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-10-16-20-06-33.gh-issue-140138.a_fhrh.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-10-16-20-06-33.gh-issue-140138.a_fhrh.rst
new file mode 100644
index 00000000000000..42a7ceec06c412
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-10-16-20-06-33.gh-issue-140138.a_fhrh.rst
@@ -0,0 +1 @@
+Fix a TSAN-reported data race and potential use-after-free when shutting down a subinterpreter with running daemon threads in free-threaded (NOGIL) builds.
diff --git a/Python/pystate.c b/Python/pystate.c
index af7828d6a030ab..f30b9737c01a46 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -488,6 +488,15 @@ free_interpreter(PyInterpreterState *interp)
     }
 }
 
+static inline void
+release_interp_owner(PyInterpreterState *interp)
+{
+    Py_ssize_t prev = _Py_atomic_add_ssize(&interp->owners, -1);
+    if (prev == 1) {
+        free_interpreter(interp);
+    }
+}
+
 #ifndef NDEBUG
 static inline int check_interpreter_whence(long);
 #endif
@@ -537,6 +546,7 @@ init_interpreter(PyInterpreterState *interp,
     interp->id = id;
 
     interp->id_refcount = 0;
+    interp->owners = 1;
 
     assert(runtime->interpreters.head == interp);
     assert(next != NULL || (interp == runtime->interpreters.main));
@@ -960,10 +970,8 @@ PyInterpreterState_Delete(PyInterpreterState *interp)
     HEAD_UNLOCK(runtime);
 
     _Py_qsbr_fini(interp);
-
     _PyObject_FiniState(interp);
-
-    free_interpreter(interp);
+    release_interp_owner(interp);
 }
 
 
@@ -1427,6 +1435,8 @@ free_threadstate(_PyThreadStateImpl *tstate)
     else {
         PyMem_RawFree(tstate);
     }
+
+    release_interp_owner(interp);
 }
 
 static void
@@ -1553,6 +1563,8 @@ new_threadstate(PyInterpreterState *interp, int whence)
     uint64_t id = interp->threads.next_unique_id;
     init_threadstate(tstate, interp, id, whence);
 
+    _Py_atomic_add_ssize(&interp->owners, 1);
+
     // Add the new thread state to the interpreter.
     PyThreadState *old_head = interp->threads.head;
     add_threadstate(interp, (PyThreadState *)tstate, old_head);