diff --git a/lld/test/MachO/lit.local.cfg b/lld/test/MachO/lit.local.cfg
--- a/lld/test/MachO/lit.local.cfg
+++ b/lld/test/MachO/lit.local.cfg
@@ -2,6 +2,12 @@
 
 import os
 
+# FIXME: The MachO back-end currently does not respect endianness when
+# accessing binary data structures, and therefore only works correctly
+# on little-endian host systems.  Skip all tests on big-endian hosts.
+if sys.byteorder == 'big':
+    config.unsupported = True
+
 # We specify the most commonly-used archs and platform versions in our tests
 # here. Tests which need different settings can just append to this, as only
 # the last value will be used.