diff --git a/lib/rbs_rails/active_record.rb b/lib/rbs_rails/active_record.rb
index f260497..5f47d90 100644
--- a/lib/rbs_rails/active_record.rb
+++ b/lib/rbs_rails/active_record.rb
@@ -85,6 +85,20 @@ class #{relation_class_name(abs: false)} < ::ActiveRecord::Relation
           class ActiveRecord_Associations_CollectionProxy < ::ActiveRecord::Associations::CollectionProxy
             include #{generated_relation_methods_name}
             include ::_ActiveRecord_Relation[#{klass_name}, #{pk_type}]
+
+            def build: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> #{klass_name}
+                     | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[#{klass_name}]
+            def create: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> #{klass_name}
+                      | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[#{klass_name}]
+            def create!: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> #{klass_name}
+                       | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[#{klass_name}]
+            def reload: () -> Array[#{klass_name}]
+
+            def replace: (Array[#{klass_name}]) -> void
+            def delete: (*#{klass_name} | #{pk_type}) -> Array[#{klass_name}]
+            def destroy: (*#{klass_name} | #{pk_type}) -> Array[#{klass_name}]
+            def <<: (*#{klass_name} | Array[#{klass_name}]) -> self
+            def prepend: (*#{klass_name} | Array[#{klass_name}]) -> self
           end
         RBS
       end
diff --git a/test/expectations/user.rbs b/test/expectations/user.rbs
index d317140..59bc17f 100644
--- a/test/expectations/user.rbs
+++ b/test/expectations/user.rbs
@@ -252,5 +252,19 @@ class User < ::ApplicationRecord
   class ActiveRecord_Associations_CollectionProxy < ::ActiveRecord::Associations::CollectionProxy
     include ::User::GeneratedRelationMethods
     include ::_ActiveRecord_Relation[::User, ::Integer]
+
+    def build: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> ::User
+             | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[::User]
+    def create: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> ::User
+              | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[::User]
+    def create!: (?ActiveRecord::Associations::CollectionProxy::_EachPair attributes) ?{ () -> untyped } -> ::User
+               | (Array[ActiveRecord::Associations::CollectionProxy::_EachPair] attributes) ?{ () -> untyped } -> Array[::User]
+    def reload: () -> Array[::User]
+
+    def replace: (Array[::User]) -> void
+    def delete: (*::User | ::Integer) -> Array[::User]
+    def destroy: (*::User | ::Integer) -> Array[::User]
+    def <<: (*::User | Array[::User]) -> self
+    def prepend: (*::User | Array[::User]) -> self
   end
 end