diff --git a/Misc/NEWS.d/next/Library/2019-03-18-14-25-36.bpo-31904.ds3d67.rst b/Misc/NEWS.d/next/Library/2019-03-18-14-25-36.bpo-31904.ds3d67.rst
new file mode 100644
index 00000000000..fd82fe086f0
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-03-18-14-25-36.bpo-31904.ds3d67.rst
@@ -0,0 +1 @@
+Fix mmap fail for VxWorks
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 33366b2d933..917c6362c11 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1164,6 +1164,13 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict)
 #ifdef MAP_ANONYMOUS
         /* BSD way to map anonymous memory */
         flags |= MAP_ANONYMOUS;
+
+        /* VxWorks only supports MAP_ANONYMOUS with MAP_PRIVATE flag */
+#ifdef __VXWORKS__
+        flags &= ~MAP_SHARED;
+        flags |= MAP_PRIVATE;
+#endif
+
 #else
         /* SVR4 method to map anonymous memory is to open /dev/zero */
         fd = devzero = _Py_open("/dev/zero", O_RDWR);