diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index eeda96c9ef..2ccf25f1df 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -3823,7 +3823,7 @@ __END__
   end
 
   def test_select_leak
-    skip 'MJIT uses too much memory' if RubyVM::MJIT.enabled?
+    skip 'assert_no_memory_leak may consider MJIT memory usage as leak' if RubyVM::MJIT.enabled?
     # avoid malloc arena explosion from glibc and jemalloc:
     env = {
       'MALLOC_ARENA_MAX' => '1',
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 1a6d87f11f..185c5c9ec5 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -647,6 +647,7 @@ CODE
   end
 
   def test_crypt
+    skip 'assert_no_memory_leak may consider MJIT memory usage as leak' if RubyVM::MJIT.enabled?
     assert_equal(S('aaGUC/JkO9/Sc'), S("mypassword").crypt(S("aa")))
     assert_not_equal(S('aaGUC/JkO9/Sc'), S("mypassword").crypt(S("ab")))
     assert_raise(ArgumentError) {S("mypassword").crypt(S(""))}