The Bischöfliches Gymnasium Petrinum (German pronunciation: [ˌpeˈtʀiːnʊm] ⓘ) is a Catholic private school of the Diocese of Linz situated on the slopes of Poestlingberg hill in Urfahr, which is a part of Linz.

The imposing structure, which is said to have nearly a thousand windows, housed the Gymnasium and an associated boarding home.

The institution, originally thought to educated future priests and prepare them for their time at the seminary, soon became one of the leading schools in Upper Austria.

During World War I, the school was used as a military hospital, which caused the erection of the Kriegerfriedhof (cemetery for dead soldiers).

After World War II, at first the red army occupied the house, the regular education being resumed only not until 1946.