diff --git a/lib/set.rb b/lib/set.rb
index 08a31e29b..1e0fbbaf6 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -288,11 +288,13 @@ def each(&block)
     end
   end
 
-  def merge(other)
-    unless other.is_a?(Enumerable)
-      raise ArgumentError, "value must be enumerable"
+  def merge(*others)
+    others.each do |other|
+      unless other.is_a?(Enumerable)
+        raise ArgumentError, "value must be enumerable"
+      end
+      other.each { |element| add(element) }
     end
-    other.each { |element| add(element) }
     self
   end
 
diff --git a/spec/library/set/merge_spec.rb b/spec/library/set/merge_spec.rb
index a8e3ffc87..3ae0da827 100644
--- a/spec/library/set/merge_spec.rb
+++ b/spec/library/set/merge_spec.rb
@@ -16,4 +16,16 @@
     -> { Set[1, 2].merge(1) }.should raise_error(ArgumentError)
     -> { Set[1, 2].merge(Object.new) }.should raise_error(ArgumentError)
   end
+
+  ruby_version_is ""..."3.3" do
+    it "accepts only a single argument" do
+      -> { Set[].merge([], []) }.should raise_error(ArgumentError, "wrong number of arguments (given 2, expected 1)")
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "accepts multiple arguments" do
+      Set[:a, :b].merge(Set[:b, :c], [:d]).should == Set[:a, :b, :c, :d]
+    end
+  end
 end