diff --git a/lib/phlex/sgml.rb b/lib/phlex/sgml.rb
index 57941ef3..701c5a5c 100644
--- a/lib/phlex/sgml.rb
+++ b/lib/phlex/sgml.rb
@@ -508,6 +508,8 @@ def json_escape(string)
 				end
 			when Phlex::SGML::SafeObject
 				v.to_s.gsub('"', """)
+			when -> (v) { v.respond_to?(:to_h) }
+				__nested_attributes__(v.to_h, "#{name}-", buffer)
 			else
 				raise Phlex::ArgumentError.new("Invalid attribute value for #{k}: #{v.inspect}.")
 			end
diff --git a/quickdraw/sgml/attributes.test.rb b/quickdraw/sgml/attributes.test.rb
index bfbd4f22..96545d5b 100644
--- a/quickdraw/sgml/attributes.test.rb
+++ b/quickdraw/sgml/attributes.test.rb
@@ -29,6 +29,16 @@
 	assert_equal error.message, "Unsafe attribute name detected: onclick."
 end
 
+test "data with hash" do
+	data = phlex { div(data: { attr: "test" }) }
+	assert_equal_html data, %(<div data-attr="test"></div>)
+end
+
+test "data with object which responds to to_h" do
+	data = phlex { div(data: Data.define(:attr).new(attr: "test")) }
+	assert_equal_html data, %(<div data-attr="test"></div>)
+end
+
 test "href with hash" do
 	error = assert_raises(Phlex::ArgumentError) do
 		phlex { a(href: {}) }