Mark Blum (May 14, 1950 - March 26, 2020) was an American actor in movies, on television and stage. He found success with a lead role as Gary Glass in the 1985 film Desperately Seeking Susan, which he followed up the next year with a supporting role as Richard Mason in Crocodile Dundee. He had a regularly recurring role as Union Bob on the Amazon Prime series Mozart in the Jungle from 2014 to 2018.

He was married to actress Janet Zarish from 2005 until his death in 2020 from COVID.