Edgar Isaac Lansbury (1887 – 28 May 1935) was a British socialist politician.
Lansbury was the son of Elizabeth (née Brine) and Labour Party politician George Lansbury. He grew up in Poplar in the East End of London, and joined the Civil Service at a young age. In 1910, he left to set up a timber merchants with his brother.
Lansbury was elected to Poplar council in 1912, serving alongside his father. He represented both the Labour Party and the Communist Party of Great Britain (CPGB). Later in the year, he worked on his father's campaign for re-election on a radical platform of women's suffrage at the Bow and Bromley by-election. He also supported Sylvia Pankhurst's East London Federation of Suffragettes, serving as Honorary Treasurer in 1915.
In 1921, Lansbury was one of 29 Poplar councillors to be jailed as a result of the Poplar Rates Rebellion, while in 1924, he was elected as a substitute member of the CPGB's Central Committee. After his first wife Minnie Lansbury died, he married actress Moyna Macgill and the two moved to Regent's Park. From 1924 to 1925, he served as Mayor of Poplar, the country's second Communist mayor after Joe Vaughan. He left the council in 1925, the same year that his first child was born, future actress Angela Lansbury. Subsequent twin sons, Bruce and Edgar, Jr., later became prominent film and TV producers.