Cox Models, a former division of Estes Industries of Penrose, Colorado, was a multimillion-dollar hobby company, is one of the hobby industry's oldest companies and is noted for its production of miniature model internal-combustion engines.

Cox model engines are used to power small model airplanes, model cars and model boats. They were in production for more than 60 years between 1945 and 2006. The business is named for founder Leroy M. Cox. He started L.M. Cox Manufacturing Co. Inc, which later became Cox Hobbies Inc., then Cox Products, before being sold to Estes Industries, when it became Cox Models. On February 7, 2009, Estes Industries stopped producing Cox engines and sold all of their remaining inventory – mainly spare parts – to several private buyers from Canada and the US. One of the new owners of the remaining Cox engine and parts inventory has launched a website with an online store.