diff --git a/.github/workflows/test-memory-leaks.yaml b/.github/workflows/test-memory-leaks.yaml
index e485c4a545f..7a1138b4cd4 100644
--- a/.github/workflows/test-memory-leaks.yaml
+++ b/.github/workflows/test-memory-leaks.yaml
@@ -12,6 +12,7 @@ jobs:
           bundler: latest
           cache-version: v1 # bump this to invalidate cache
       - run: sudo apt-get update && (sudo apt-get install -y valgrind || sleep 5 && sudo apt-get install -y valgrind) && valgrind --version
+      - run: gem update --system 3.5.23 # TODO: This is a workaround for a buggy rubygems in 3.4.0-preview2; remove once stable version 3.4 is out
       - run: bundle exec rake compile spec:profiling:memcheck
   test-asan:
     # Temporarily ruby-asan builds changes
diff --git a/suppressions/ruby-3.4.supp b/suppressions/ruby-3.4.supp
index 9910e76b275..646151fa9fb 100644
--- a/suppressions/ruby-3.4.supp
+++ b/suppressions/ruby-3.4.supp
@@ -45,6 +45,21 @@
   ...
 }
 
+# When a Ruby process forks, it looks like Ruby doesn't clean up the memory of old threads?
+{
+  ruby-native-thread-memory-3
+  Memcheck:Leak
+  fun:calloc
+  fun:calloc1
+  fun:rb_gc_impl_calloc
+  fun:ruby_xcalloc
+  fun:native_thread_alloc
+  fun:native_thread_create_dedicated
+  fun:native_thread_create
+  fun:thread_create_core
+  ...
+}
+
 # We don't care about the pkg-config external tool
 {
   pkg-config-memory