It depends whether you mean in the wild or captive. One lived with a herpetologist in Switzerland for 18 years. In the wild some live 8 or more years. In captivity most people kill them in a few...
Horned Lizards in captivity with neophytes typically don't last but a few months. They may live at least 3 years, sometimes more, with some experienced keepers. One lived 18 years with a...