Julia Baird (née Dykins; born 5 March 1947) is a British retired teacher and author. She is the younger half-sister of English musician John Lennon, and is the eldest daughter of his mother Julia Lennon and John 'Bobby' Albert Dykins. She also has an older maternal half-sister, Ingrid Pedersen. Her younger sister is Jacqueline 'Jackie' Dykins (born 26 October 1949).
Lennon started visiting the Dykins' house in 1951. After the death of Julia Lennon in 1958, Harriet and Norman Birch were appointed guardians of Julia and Jackie, ignoring Dykins' parentage, as he had never legally married their mother. Lennon invited the Dykins sisters to visit after the success of the Beatles, when he was living in Kenwood, Weybridge, with his then-wife, Cynthia Lennon.
Julia Dykins (Baird) married Allen Baird in 1968 and moved to Belfast. They had three children together but were divorced in 1981. Baird worked as a French language teacher and special needs teacher, and after Lennon's death she wrote John Lennon, My Brother (with Geoffrey Giuliano) and gave up working in 2004 to write Imagine This – Growing up with my brother John Lennon. In 2009, the book was adapted into the film Nowhere Boy. She is now a director of Cavern City Tours in Liverpool.