The Honourable Anna Maria Heywood, Lady Barlow (c. 1874 – 28 May 1965) was an English welfare reformer and Liberal politician.
Anna Maria Heywood Denman was born around 1874 in Liverpool, the daughter of the Hon. Richard Denman and Helen McMicking. Her brother was Thomas Denman, 3rd Baron Denman. She was educated privately. In 1895 she married John Emmott Barlow, the Liberal MP for Frome in Somerset and senior partner in his family businesses with principal interests in textiles, tea and coffee and rubber. They had two sons and two daughters. Her son John who succeeded his father to become the second baronet was Liberal candidate for Northwich in 1929. He later became a National Liberal representing Eddisbury from 1945–1950 and then a fully fledged Conservative being MP for Middleton and Prestwich from 1951–1966. In religion, Sir John and Lady Barlow were Quakers, Lady Barlow having converted to that denomination in about 1911.