Otto Karl Robert Wernicke (30 September 1893, Osterode am Harz – 7 November 1965) was a German actor. He was best known for his role as police inspector Karl Lohmann in the two Fritz Lang films M and The Testament of Dr. Mabuse. He was the first one to portray Captain Smith in the first "official" Titanic film.
Wernicke was married to a Jewish woman. Only due to a special permit and substantial donation to the Nazi Party was he allowed to continue his work in Nazi Germany. He appeared in the 1944-45 propaganda epic Kolberg.