The Cauayan City National High School is a public educational institution established in Cauayan, Isabela, Philippines. It was established on June 3, 1997 as an extension of Cauayan Polytechnic College, now Isabela State University-Cauayan Campus. It was formerly named as Cauayan National High School since its inception and later renamed to its present name when Cauayan, Isabela became a city on March 30, 2001. In 2013, Cauayan City National High School won as the greenest school in the Philippines.