Mark Grotjahn (born 1968 in Pasadena, California, U.S.) is an American painter, living and working in Los Angeles. He received his MFA from the University of California, Berkeley, and his BFA from the University of Colorado at Boulder. He is best known for abstract work and bold geometric paintings. Grotjahn's work has been exhibited internationally at galleries and museums such as UCLA Hammer Museum in Los Angeles, the Museum of Contemporary Art, Chicago, the Whitney Museum of American Art, and P.S.1 Contemporary Art Center in New York, Museum am Ostwall, Dortmund, and Neuer Aachener, Kunstverein, in Germany, and The Royal Academy in London. His work is featured in several prominent collections including the Carnegie Museum of Art in Pittsburgh, the Museum of Contemporary Art, Los Angeles, The Museum of Modern Art in New York, and the Saatchi Gallery in London.