Isabella Burns (Isabella Begg) (1771–1858) or Isobel Burns (Isobel Begg) was the youngest sister of the poet Robert Burns, born to William Burness and Agnes Broun at Mount Oliphant Farm on the 27 June 1771 and christened on 2 July 1771 by Rev. William McGill, a friend of her father. When she died she was the last member of Robert Burns's immediate family and when living at Bridge House in Alloway for the last sixteen years of her life she entertained many visitors who were interested in his life and works. She was the source of many published insights into Burns's life, character and loves. Her siblings knew her as 'Isbal'.

Agnes Broun, Agnes Brown or Agnes Burnes, was the mother of Scotland's national poet, Robert Burns. Agnes's father, Gilbert (1708–1774), was the tenant of the 300-acre (120 ha) farm of Craigenton, in Kirkoswald parish, South Ayrshire, Scotland.