Horst Tappert (26 May 1923 – 13 December 2008) was a German movie and television actor who played Inspector Stephan Derrick in the television drama Derrick.
Horst Tappert was born on 26 May 1923 in Elberfeld (now Wuppertal), Germany. His father was a civil servant. Following high school, Tappert was drafted into the German army in World War II and ended up as a prisoner of war. Like the later author of the Derrick series, Herbert Reinecker, Tappert joined the Waffen-SS. Initially a member of the SS-Flak-Ersatzabteilung (Arolsen), he was listed as a member of 3rd SS Division Totenkopf in March 1943. Following the war, he was hired as a bookkeeper at a theatre in Stendal, Germany, and became interested in acting. He took acting classes and gave his stage debut in Stendal, playing Dr. Stribel in Paul Helwig's Die Flitterwochen.
In the following years, he changed employers several times and, in 1956, started working at the Kammerspiele, Munich. An independent actor since 1967, he worked as an actor until he died.