The Mary and Leigh Block Museum of Art is an art museum located on the campus of Northwestern University in Evanston, Illinois. The Block Museum was established in 1980 by Chicago art collectors Mary and Leigh B. Block (former vice president of Inland Steel Company). The original conception of the museum was modeled on the German kunsthalle tradition, with no permanent collection, and a series of changing temporary exhibits. However, the Block Museum soon began to acquire a permanent collection as the University transferred many of its art pieces to the museum.

The museum building was constructed in 1980 and was designed by Chicago architecture firm Loebl, Schlossman, and Hackl. The Block's outdoor sculpture garden was established in 1989. The museum building was expanded in 2000, with a design by Chicago architectural firm Lohan Associates. The 2000 expansion tripled the museum's gallery size. The museum's Pick-Laudati Auditorium is also home to the Block Cinema, a repertory film series featuring international, classic and arthouse cinema. The selection of films at Block Cinema is curated in part by students in the Northwestern University Film and Projection Society.

The museum currently has over 4,000 pieces in its collection. The museum is particularly known for its sculpture garden as well as its collection of works on paper. Among its collections are strong holdings of works by Chicago-based artists, nineteenth-century prints and drawings and photography. In addition to its permanent collection, the museum still dedicates one third of its space to temporary and traveling exhibitions.