--- a/unit_test/convert_argb_test.cc
+++ b/unit_test/convert_argb_test.cc
@@ -40,7 +40,7 @@
 
 // Some functions fail on big endian. Enable these tests on all cpus except
 // PowerPC, but they are not optimized so disabled by default.
-#if !defined(DISABLE_SLOW_TESTS) && !defined(__powerpc__)
+#if !defined(DISABLE_SLOW_TESTS) && !defined(__powerpc__) && !defined(__s390x__)
 #define LITTLE_ENDIAN_ONLY_TEST 1
 #endif
 #if !defined(DISABLE_SLOW_TESTS) || defined(__x86_64__) || defined(__i386__)
--- a/unit_test/convert_test.cc
+++ b/unit_test/convert_test.cc
@@ -40,7 +40,7 @@
 
 // Some functions fail on big endian. Enable these tests on all cpus except
 // PowerPC, but they are not optimized so disabled by default.
-#if !defined(DISABLE_SLOW_TESTS) && !defined(__powerpc__)
+#if !defined(DISABLE_SLOW_TESTS) && !defined(__powerpc__) && !defined(__s390x__)
 #define LITTLE_ENDIAN_ONLY_TEST 1
 #endif
 #if !defined(DISABLE_SLOW_TESTS) || defined(__x86_64__) || defined(__i386__)