diff --git a/Lib/test/test_utf8_mode.py b/Lib/test/test_utf8_mode.py
index 220ff34a1189ce..2429b00459be51 100644
--- a/Lib/test/test_utf8_mode.py
+++ b/Lib/test/test_utf8_mode.py
@@ -12,7 +12,7 @@
 
 MS_WINDOWS = (sys.platform == 'win32')
 POSIX_LOCALES = ('C', 'POSIX')
-
+VXWORKS = (sys.platform == "vxworks")
 
 class UTF8ModeTests(unittest.TestCase):
     DEFAULT_ENV = {
@@ -225,7 +225,7 @@ def check(utf8_opt, expected, **kw):
             with self.subTest(LC_ALL=loc):
                 check('utf8', [arg_utf8], LC_ALL=loc)
 
-        if sys.platform == 'darwin' or support.is_android:
+        if sys.platform == 'darwin' or support.is_android or VXWORKS:
             c_arg = arg_utf8
         elif sys.platform.startswith("aix"):
             c_arg = arg.decode('iso-8859-1')
diff --git a/Misc/NEWS.d/next/Tests/2019-03-19-17-39-25.bpo-31904.QxhhRx.rst b/Misc/NEWS.d/next/Tests/2019-03-19-17-39-25.bpo-31904.QxhhRx.rst
new file mode 100644
index 00000000000000..95771508619e5b
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2019-03-19-17-39-25.bpo-31904.QxhhRx.rst
@@ -0,0 +1 @@
+Fix test_utf8_mode on VxWorks: Python always use UTF-8 on VxWorks.