diff --git a/bootstraptest/runner.rb b/bootstraptest/runner.rb
index 3d423902545a8d..d7289f5a95b14f 100755
--- a/bootstraptest/runner.rb
+++ b/bootstraptest/runner.rb
@@ -720,4 +720,8 @@ def check_coredump
   end
 end
 
+def mmtk?
+  `#{BT.ruby} -e 'p defined?(GC::MMTk)'`.strip == '"constant"'
+end
+
 exit main
diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index b29db7ab0eb8de..12d0fff5a642e1 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 # Ractor.current returns a current ractor
 assert_equal 'Ractor', %q{
   Ractor.current.class
diff --git a/bootstraptest/test_thread.rb b/bootstraptest/test_thread.rb
index 5361828403e7df..5648769898e2f9 100644
--- a/bootstraptest/test_thread.rb
+++ b/bootstraptest/test_thread.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 show_limit %q{
   threads = []
   begin
diff --git a/bootstraptest/test_yjit.rb b/bootstraptest/test_yjit.rb
index 7158486d5048ff..6313b82f73a732 100644
--- a/bootstraptest/test_yjit.rb
+++ b/bootstraptest/test_yjit.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 assert_equal 'true', %q{
   # regression test for tracking type of locals for too long
   def local_setting_cmp(five)
diff --git a/bootstraptest/test_yjit_30k_ifelse.rb b/bootstraptest/test_yjit_30k_ifelse.rb
index c3afa95e4dd718..23cd61beb2d971 100644
--- a/bootstraptest/test_yjit_30k_ifelse.rb
+++ b/bootstraptest/test_yjit_30k_ifelse.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 # This is a torture test for the JIT.
 # There are 30K tiny methods with if-else statements in a 30-deep call hierarchy.
 assert_equal '100000', %q{
diff --git a/bootstraptest/test_yjit_30k_methods.rb b/bootstraptest/test_yjit_30k_methods.rb
index f2acea4ce5d274..c1c2b7edda40db 100644
--- a/bootstraptest/test_yjit_30k_methods.rb
+++ b/bootstraptest/test_yjit_30k_methods.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 # This is a torture test for the JIT.
 # There are 30K tiny methods in a 30-deep call hierarchy.
 assert_equal '1000000', %q{
diff --git a/bootstraptest/test_yjit_rust_port.rb b/bootstraptest/test_yjit_rust_port.rb
index e399e0e49ef637..b7d3fc62dcc9af 100644
--- a/bootstraptest/test_yjit_rust_port.rb
+++ b/bootstraptest/test_yjit_rust_port.rb
@@ -1,3 +1,5 @@
+return if mmtk?
+
 # Simple tests that we know we can pass
 # To keep track of what we got working during the Rust port
 # And avoid breaking/losing functionality