RecursiveOpenStruct is a subclass of OpenStruct. It differs from OpenStruct in that it allows nested hashes to be treated in a recursive fashion. For example: ros = RecursiveOpenStruct.new({ :a => { :b => 'c' } }) ros.a.b # 'c' Also, nested hashes can still be accessed as hashes: ros.a_as_a_hash # { :b => 'c' }