diff --git a/lib/delegate.rb b/lib/delegate.rb
index 838de67..b5224ea 100644
--- a/lib/delegate.rb
+++ b/lib/delegate.rb
@@ -345,10 +345,16 @@ def __setobj__(obj)
 end
 
 def Delegator.delegating_block(mid) # :nodoc:
-  lambda do |*args, &block|
+  prok = lambda do |*args, &block|
     target = self.__getobj__
     target.__send__(mid, *args, &block)
-  end.ruby2_keywords
+  end
+  prok.ruby2_keywords
+  if defined?(Ractor.shareable_proc)
+    Ractor.shareable_proc(&prok)
+  else
+    prok
+  end
 end
 
 #
diff --git a/test/test_delegate.rb b/test/test_delegate.rb
index ff7998e..ca170e3 100644
--- a/test/test_delegate.rb
+++ b/test/test_delegate.rb
@@ -390,4 +390,20 @@ def test(a, k:) [a, k]; end
     a = DelegateClass(k).new(k.new)
     assert_equal([1, 0], a.test(1, k: 0))
   end
+
+  def test_delegate_class_can_be_used_in_ractors
+    omit "no Ractor#value" unless defined?(Ractor) && Ractor.method_defined?(:value)
+    require_path = File.expand_path(File.join(__dir__, "..", "lib", "delegate.rb"))
+    raise "file doesn't exist: #{require_path}" unless File.exist?(require_path)
+    assert_ractor <<-RUBY
+      require "#{require_path}"
+      class MyClass < DelegateClass(Array);end
+      values = 2.times.map do
+        Ractor.new do
+          MyClass.new([1,2,3]).at(0)
+        end
+      end.map(&:value)
+      assert_equal [1,1], values
+    RUBY
+  end
 end