diff --git a/test/cctest/cctest.status b/test/cctest/cctest.status
index e37f3dbbef..b8d95b396f 100644
--- a/test/cctest/cctest.status
+++ b/test/cctest/cctest.status
@@ -101,6 +101,12 @@ test-threads/ThreadJoinSelf: SKIP
 ##############################################################################
 [ $arch == nacl_ia32 || $arch == nacl_x64 ]
 
+# NaCl builds have problems with threaded tests since Pepper_28.
+# V8 Issue 2786
+test-api/Threading1: SKIP
+test-lockers/MultithreadedParallelIsolates: SKIP
+test-lockers/ExtensionsRegistration: SKIP
+
 # These tests fail as there is no /tmp directory in Native Client.
 test-log/LogAccessorCallbacks: SKIP
 test-log/LogCallbacks: SKIP
diff --git a/test/mjsunit/mjsunit.status b/test/mjsunit/mjsunit.status
index 7e8d5b9584..50a4c7090f 100644
--- a/test/mjsunit/mjsunit.status
+++ b/test/mjsunit/mjsunit.status
@@ -228,6 +228,10 @@ debug-liveedit-double-call: SKIP
 # As noted above none of them are run in the arm.debug case.
 fuzz-natives-part4: SKIP
 
+# NaCl builds have problems with this test since Pepper_28.
+# V8 Issue 2786
+math-exp-precision: SKIP
+
 # Requires bigger stack size in the Genesis and if stack size is increased,
 # the test requires too much time to run.  However, the problem test covers
 # should be platform-independent.