diff --git a/Changelog.md b/Changelog.md
index 8594a7c..4d6061c 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## [1.1.1] - 2024-05-21
+### Fixed
+- Fixed Definition::Model inheritance
+
 ## [1.1.0] - 2023-11-22
 ### Changes
 - Improved performance
diff --git a/Gemfile.lock b/Gemfile.lock
index 9eb0e27..d209a7d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    definition (1.1.0)
+    definition (1.1.1)
       activesupport
       i18n
 
diff --git a/lib/definition/model.rb b/lib/definition/model.rb
index 5f8a8ef..b92b862 100644
--- a/lib/definition/model.rb
+++ b/lib/definition/model.rb
@@ -37,7 +37,12 @@ def _define_attr_accessor(key)
       end
 
       def _definition
-        @_definition ||= ::Definition.Keys {}
+        @_definition ||= if superclass == ::Definition::Model
+                           ::Definition.Keys {}
+                         else
+                           # Create a deep copy of parent's definition
+                           Marshal.load(Marshal.dump(superclass._definition))
+                         end
       end
     end
 
diff --git a/lib/definition/version.rb b/lib/definition/version.rb
index e2c8e4d..50ccecb 100644
--- a/lib/definition/version.rb
+++ b/lib/definition/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Definition
-  VERSION = "1.1.0"
+  VERSION = "1.1.1"
 end
diff --git a/spec/lib/definition/model_spec.rb b/spec/lib/definition/model_spec.rb
index 5d628b7..bade42c 100644
--- a/spec/lib/definition/model_spec.rb
+++ b/spec/lib/definition/model_spec.rb
@@ -131,6 +131,61 @@
         end.to raise_error(Definition::InvalidModelError, /bar/)
       end
     end
+
+    context "with inheritance" do
+      subject(:new) { child_test_model_class.new(**kwargs) }
+
+      let(:child_test_model_class) do
+        ParentModel = test_model_class
+        Class.new(ParentModel) do
+          required :age, Definition.Type(Integer)
+          optional :phone, Definition.Type(String)
+        end
+      end
+
+      context "with required keywords only" do
+        let(:kwargs) { { name: "John", age: 24 } }
+
+        it "instantiates the model" do
+          expect(new.name).to eq("John")
+          expect(new.email).to be_nil
+          expect(new.age).to eq(24)
+          expect(new.phone).to be_nil
+        end
+      end
+
+      context "with required and optional keywords" do
+        let(:kwargs) { { name: "John", email: "test@test.com", age: 24, phone: "+4312345" } }
+
+        it "instantiates the model" do
+          expect(new.name).to eq("John")
+          expect(new.email).to eq("test@test.com")
+          expect(new.age).to eq(24)
+          expect(new.phone).to eq("+4312345")
+        end
+      end
+
+      it "throws error when parent's required attributes are missing" do
+        expect do
+          child_test_model_class.new(age: 24)
+        end.to raise_error(Definition::InvalidModelError, /name/)
+      end
+
+      it "throws error when child's required attributes are missing" do
+        expect do
+          child_test_model_class.new(name: "John")
+        end.to raise_error(Definition::InvalidModelError, /age/)
+      end
+
+      it "doesn't change parent's defintion" do
+        expect do
+          Class.new(test_model_class) do
+            required :required_child_attribute, Definition.Type(Integer)
+            optional :optional_child_attribute, Definition.Type(String)
+          end
+        end.not_to(change { test_model_class._definition.keys })
+      end
+    end
   end
 
   describe ".to_h" do