Hamar katedralskole (English: Hamar Cathedral School) is an upper secondary school in Hamar, Norway. Founded in 1153 as Schola cathedralis hamarensis, it is the second oldest school in Norway together with Bergen katedralskole and Oslo katedralskole, which were founded the same year, one year after the founding of Trondheim katedralskole. The school was closed from 1602 until 1876, when it was reopened under the name Hamar offentlige skole for høyere allmenndannelse. The old name was reintroduced in 1936. The current headmaster is Stig Johannessen.