diff --git a/lib/mongoid/extensions/set.rb b/lib/mongoid/extensions/set.rb
index 574723f845..a9072678e4 100644
--- a/lib/mongoid/extensions/set.rb
+++ b/lib/mongoid/extensions/set.rb
@@ -59,6 +59,16 @@ def mongoize(object)
           when ::Array then ::Array.mongoize(object).uniq
           end
         end
+
+        # Returns whether the object's size can be changed.
+        #
+        # @example Is the object resizable?
+        #   Set.resizable?
+        #
+        # @return [ true ] true.
+        def resizable?
+          true
+        end
       end
     end
   end
diff --git a/spec/mongoid/extensions/array_spec.rb b/spec/mongoid/extensions/array_spec.rb
index 6c007320fb..097e60ee36 100644
--- a/spec/mongoid/extensions/array_spec.rb
+++ b/spec/mongoid/extensions/array_spec.rb
@@ -362,7 +362,7 @@
     end
   end
 
-  describe "#resiable?" do
+  describe "#resizable?" do
 
     it "returns true" do
       expect([]).to be_resizable
diff --git a/spec/mongoid/extensions/set_spec.rb b/spec/mongoid/extensions/set_spec.rb
index f81e43c5fc..fb4979a7c6 100644
--- a/spec/mongoid/extensions/set_spec.rb
+++ b/spec/mongoid/extensions/set_spec.rb
@@ -137,4 +137,18 @@
       end
     end
   end
+
+  describe ".resizable?" do
+
+    it "returns true" do
+      expect(Set).to be_resizable
+    end
+  end
+
+  describe "#resizable?" do
+
+    it "returns true" do
+      expect(Set.new).to be_resizable
+    end
+  end
 end