The Metropolitan Borough of Poplar was between 1899 and 1965 a metropolitan borough in the County of London. It became part of the London Borough of Tower Hamlets.

It bordered Hackney, Stepney, and Bethnal Green. It included the districts of Bow, Bromley-by-Bow, Blackwall, Poplar and the Isle of Dogs.

In the early 1920s the Borough Council, and the Poor Law Union were engaged in a dispute with the London County Council and central government over poor law rates - it wished to pay out of work people more than usually permitted; and to get wealthier West End boroughs to contribute to its expenses. Several councillors were imprisoned briefly in 1921 in relation to this.