"O Jesu Christe, wahres Licht" is a Lutheran hymn by the German Baroque poet, Lutheran minister and hymn-writer Johann Heermann. The text was first published in 1630 during the Thirty Years' War. It is a prayer for enlightenment of those who are ignorant, and of those who turned away. It was associated with a melody from Nürnberg, dating to 1676. The hymn is part of modern German hymnals, both Protestant and Catholic. It was translated to English as "O Christ, our true and only light".

Johann Heermann was a German poet and hymnodist. He is commemorated in the Calendar of Saints of the Lutheran Church on 26 October with Philipp Nicolai and Paul Gerhardt.