The Blot is a 1921 American silent drama film directed by Lois Weber, who also co-wrote (with Marion Orth) and produced the film (with her then-husband, Phillips Smalley). The film tackles the social problem of genteel poverty, focusing on a struggling family. It stars Philip Hubbard, Margaret McWade, Louis Calhern, and Claire Windsor.

Weber filmed in real locations, using as much natural lighting as possible. Scenes were filmed on location around Los Angeles, particularly at the old University of Los Angeles campus, now Los Angeles City College. Many supporting roles were given to non-professionals.

The Blot was restored by Kevin Brownlow and David Gill for British television. Brownlow singles out the film for praise in his book Behind the Mask of Innocence (1990). The Blot screened at the San Francisco Silent Film Festival in 2002. It was released on DVD in 2006 with expert audio commentary by film historian Shelley Stamp.