diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 6f1aaff87bb..94e4eb936ec 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -513,6 +513,13 @@ always available.
    could be useful to restore the actual files to known working file objects in
    case they have been overwritten with a broken object.
 
+  .. note::
+
+    Under some conditions ``stdin``, ``stdout`` and ``stderr`` as well as the
+    original values ``__stdin__``, ``__stdout__`` and ``__stderr__`` can be
+    None. It is usually the case for Windows GUI apps that aren't connected to
+    a console and Python apps started with :program:`pythonw`.
+
 
 .. data:: tracebacklimit
 
@@ -571,3 +578,4 @@ always available.
    Module :mod:`site`
       This describes how to use .pth files to extend ``sys.path``.
 
+
diff --git a/Misc/NEWS b/Misc/NEWS
index c79b53109ed..f68ac904ae2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -34,6 +34,11 @@ Core and Builtins
 - Added a new option -b to issues warnings (-bb for errors) about certain
   operations between bytes/buffer and str like str(b'') and comparsion.
 
+- The standards streams sys.stdin, stdout and stderr may be None when the
+  when the C runtime library returns an invalid file descriptor for the
+  streams (fileno(stdin) < 0). For now this happens only for Windows GUI
+  apps and scripts started with `pythonw.exe`.
+
 Extension Modules
 -----------------
 
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index 6d6022eedfd..5d69911ff66 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -363,7 +363,7 @@ PyFile_NewStdPrinter(int fd)
 {
 	PyStdPrinter_Object *self;
 
-	if ((fd != fileno(stdout) && fd != fileno(stderr)) || fd < 0) {
+	if (fd != fileno(stdout) && fd != fileno(stderr)) {
 		/* not enough infrastructure for PyErr_BadInternalCall() */
 		return NULL;
 	}
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 0b3935ab697..82f8e373caf 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -717,7 +717,7 @@ initstdio(void)
 	PyObject *bimod = NULL;
 	PyObject *m;
 	PyObject *std = NULL;
-	int status = 0;
+	int status = 0, fd;
 
 	/* Hack to avoid a nasty recursion issue when Python is invoked
 	   in verbose mode: pre-import the Latin-1 and UTF-8 codecs */
@@ -748,35 +748,72 @@ initstdio(void)
 	}
 
 	/* Set sys.stdin */
-	if (!(std = PyFile_FromFd(fileno(stdin), "<stdin>", "r", -1,
-				  NULL, "\n", 0))) {
+	fd = fileno(stdin);
+	/* Under some conditions stdin, stdout and stderr may not be connected
+	 * and fileno() may point to an invalid file descriptor. For example
+	 * GUI apps don't have valid standard streams by default.
+	 */
+	if (fd < 0) {
+#ifdef MS_WINDOWS
+		std = Py_None;
+		Py_INCREF(std);
+#else
 		goto error;
+#endif
 	}
+	else {
+		if (!(std = PyFile_FromFd(fd, "<stdin>", "r", -1, NULL, 
+					  "\n", 0))) {
+			goto error;
+		}
+	} /* if (fd < 0) */
 	PySys_SetObject("__stdin__", std);
 	PySys_SetObject("stdin", std);
 	Py_DECREF(std);
 
 	/* Set sys.stdout */
-	if (!(std = PyFile_FromFd(fileno(stdout), "<stdout>", "w", -1,
-				  NULL, "\n", 0))) {
-            goto error;
-        }
+	fd = fileno(stdout);
+	if (fd < 0) {
+#ifdef MS_WINDOWS
+		std = Py_None;
+		Py_INCREF(std);
+#else
+		goto error;
+#endif
+	}
+	else {
+		if (!(std = PyFile_FromFd(fd, "<stdout>", "w", -1, NULL, 
+					  "\n", 0))) {
+			goto error;
+		}
+	} /* if (fd < 0) */
 	PySys_SetObject("__stdout__", std);
 	PySys_SetObject("stdout", std);
 	Py_DECREF(std);
 
 #if 1 /* Disable this if you have trouble debugging bootstrap stuff */
 	/* Set sys.stderr, replaces the preliminary stderr */
-	if (!(std = PyFile_FromFd(fileno(stderr), "<stderr>", "w", -1,
-				  NULL, "\n", 0))) {
-            goto error;
-        }
+	fd = fileno(stderr);
+	if (fd < 0) {
+#ifdef MS_WINDOWS
+		std = Py_None;
+		Py_INCREF(std);
+#else
+		goto error;
+#endif
+	}
+	else {
+		if (!(std = PyFile_FromFd(fd, "<stderr>", "w", -1, NULL, 
+					  "\n", 0))) {
+			goto error;
+		}
+	} /* if (fd < 0) */
         PySys_SetObject("__stderr__", std);
 	PySys_SetObject("stderr", std);
 	Py_DECREF(std);
 #endif
 
-        if (0) {
+	if (0) {
   error:
                 status = -1;
         }