diff -ur a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
--- a/Doc/library/stdtypes.rst	2016-12-16 19:32:21.000000000 -0500
+++ b/Doc/library/stdtypes.rst	2016-12-16 19:34:50.000000000 -0500
@@ -2316,7 +2316,7 @@
 
    This :class:`bytes` class method returns a bytes object, decoding the
    given string object.  The string must contain two hexadecimal digits per
-   byte, with ASCII spaces being ignored.
+   byte, with ASCII whitespace being ignored.
 
    >>> bytes.fromhex('2Ef0 F1f2  ')
    b'.\xf0\xf1\xf2'
@@ -2384,7 +2384,7 @@
 
    This :class:`bytearray` class method returns bytearray object, decoding
    the given string object.  The string must contain two hexadecimal digits
-   per byte, with ASCII spaces being ignored.
+   per byte, with ASCII whitespace being ignored.
 
    >>> bytearray.fromhex('2Ef0 F1f2  ')
    bytearray(b'.\xf0\xf1\xf2')
diff -ur a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
--- a/Lib/test/test_bytes.py	2016-12-09 19:05:07.000000000 -0500
+++ b/Lib/test/test_bytes.py	2016-12-16 19:37:12.000000000 -0500
@@ -293,6 +293,14 @@
         b = bytearray([0x1a, 0x2b, 0x30])
         self.assertEqual(self.type2test.fromhex('1a2B30'), b)
         self.assertEqual(self.type2test.fromhex('  1A 2B  30   '), b)
+
+        # check that ASCII whitespace is ignored
+        self.assertEqual(self.type2test.fromhex(' 1A\n2B\t30\v'), b)
+        for c in "\x09\x0A\x0B\x0C\x0D\x20":
+            self.assertEqual(self.type2test.fromhex(c), self.type2test())
+        for c in "\x1C\x1D\x1E\x1F\x85\xa0\u2000\u2002\u2028":
+            self.assertRaises(ValueError, self.type2test.fromhex, c)
+
         self.assertEqual(self.type2test.fromhex('0000'), b'\0\0')
         self.assertRaises(TypeError, self.type2test.fromhex, b'1B')
         self.assertRaises(ValueError, self.type2test.fromhex, 'a')
diff -ur a/Objects/bytesobject.c b/Objects/bytesobject.c
--- a/Objects/bytesobject.c	2016-12-09 19:01:49.000000000 -0500
+++ b/Objects/bytesobject.c	2016-12-09 19:02:39.000000000 -0500
@@ -2379,10 +2379,10 @@
     end = str + hexlen;
     while (str < end) {
         /* skip over spaces in the input */
-        if (*str == ' ') {
+        if (Py_ISSPACE(*str)) {
             do {
                 str++;
-            } while (*str == ' ');
+            } while (Py_ISSPACE(*str));
             if (str >= end)
                 break;
         }