diff --git a/README.md b/README.md
index 726a5b83..2dd7a669 100644
--- a/README.md
+++ b/README.md
@@ -241,6 +241,18 @@ JSON::Validator.validate(schema, { "a" => 1 }, :parse_data => false)
 # => false
 JSON::Validator.validate(schema, '{ "a": 1 }', :parse_data => false)
 
+#
+# with the `:nullable` option set to true, any key with null value will be evaluated to true
+#
+schema = {
+  "type": "object",
+  "properties": {
+      "github_url": { "type": "string", "nullable": true }
+    }
+}
+# => true
+JSON::Validator.validate!(schema, { "github_url" => null })
+
 #
 # with the `:parse_integer` option set to false, the integer value given as string will not be parsed.
 #
diff --git a/lib/json-schema/attribute.rb b/lib/json-schema/attribute.rb
index 31eb98f7..29e1e572 100644
--- a/lib/json-schema/attribute.rb
+++ b/lib/json-schema/attribute.rb
@@ -33,8 +33,10 @@ def self.validation_errors(validator)
         'any' => Object,
       }
 
-      def self.data_valid_for_type?(data, type)
+      def self.data_valid_for_type?(data, type, nullable: false)
         valid_classes = TYPE_CLASS_MAPPINGS.fetch(type) { return true }
+        valid_classes = [valid_classes, NilClass] if nullable
+        valid_classes.flatten! if valid_classes.is_a?(Array)
         Array(valid_classes).any? { |c| data.is_a?(c) }
       end
 
diff --git a/lib/json-schema/attributes/type.rb b/lib/json-schema/attributes/type.rb
index 149ac6af..76792408 100644
--- a/lib/json-schema/attributes/type.rb
+++ b/lib/json-schema/attributes/type.rb
@@ -5,10 +5,12 @@ class Schema
     class TypeAttribute < Attribute
       def self.validate(current_schema, data, fragments, processor, validator, options = {})
         union = true
+        nullable = false
         if options[:disallow]
           types = current_schema.schema['disallow']
         else
           types = current_schema.schema['type']
+          nullable = current_schema.schema['nullable']
         end
 
         if !types.is_a?(Array)
@@ -22,7 +24,7 @@ def self.validate(current_schema, data, fragments, processor, validator, options
 
         types.each_with_index do |type, type_index|
           if type.is_a?(String)
-            valid = data_valid_for_type?(data, type)
+            valid = data_valid_for_type?(data, type, nullable: nullable)
           elsif type.is_a?(Hash) && union
             # Validate as a schema
             schema = JSON::Schema.new(type, current_schema.uri, validator)
diff --git a/lib/json-schema/attributes/type_v4.rb b/lib/json-schema/attributes/type_v4.rb
index f5d5a3a7..cc85186d 100644
--- a/lib/json-schema/attributes/type_v4.rb
+++ b/lib/json-schema/attributes/type_v4.rb
@@ -6,12 +6,13 @@ class TypeV4Attribute < Attribute
       def self.validate(current_schema, data, fragments, processor, validator, options = {})
         union = true
         types = current_schema.schema['type']
+        nullable = current_schema.schema['nullable']
         if !types.is_a?(Array)
           types = [types]
           union = false
         end
 
-        return if types.any? { |type| data_valid_for_type?(data, type) }
+        return if types.any? { |type| data_valid_for_type?(data, type, nullable: nullable) }
 
         types = types.map { |type| type.is_a?(String) ? type : '(schema)' }.join(', ')
         message = format(
diff --git a/test/initialize_data_test.rb b/test/initialize_data_test.rb
index 9a531258..ba1662bf 100644
--- a/test/initialize_data_test.rb
+++ b/test/initialize_data_test.rb
@@ -379,4 +379,15 @@ def test_parse_hash_with_instantiated_validator
     assert_raises(TypeError) { v.validate(data) }
     assert_raises(TypeError) { v.validate(data) }
   end
+
+  def test_nullable_param
+    schema = { 'type' => 'object', 'properties' => { 'a' => { 'type' => 'string', 'nullable' => true } } }
+    data = { 'a' => nil }
+
+    assert(JSON::Validator.validate(schema, data))
+
+    schema = { 'type' => 'object', 'properties' => { 'a' => { 'type' => 'string' } } }
+
+    refute(JSON::Validator.validate(schema, data))
+  end
 end