Walter Richard Sickert RA RBA (31 May 1860 – 22 January 1942) was a German-born British painter and printmaker who was a member of the Camden Town Group of Post-Impressionist artists in early 20th-century London. He was an important influence on distinctively British styles of avant-garde art in the mid and late 20th century.

Sickert was a cosmopolitan and an eccentric who often favoured ordinary people and urban scenes as his subjects. His work includes portraits of well-known personalities and images derived from press photographs. He is considered a prominent figure in the transition from Impressionism to Modernism.

Decades after his death, several authors and researchers theorised that Sickert might have been the London-based serial killer Jack the Ripper, but the claim has since largely been dismissed.