Ernst Deger (15 April 1809, Bockenem – 27 January 1885, Düsseldorf) was a German religious artist, in the style of the Nazarene movement.
On behalf of the Kunstverein für die Rheinlande und Westfalen [de] (Artists' Association), he created an altarpiece for the Church of St. Andreas, showing Mary as the Queen of Heaven.
His next major project, commissioned by King Frederick William IV of Prussia, involved a series of wall paintings at Stolzenfels Castle.
During its final phases, he was assisted by Peter Molitor, a struggling young artist from Koblenz.
His best-known students included Franz Paul Massau [de] and Friedrich Stummel.