Donald Woods Winnicott (7 April 1896 – 25 January 1971) was an English paediatrician and psychoanalyst who was especially influential in the field of object relations theory and developmental psychology. He was a leading member of the British Independent Group of the British Psychoanalytical Society, President of the British Psychoanalytical Society twice (1956–1959 and 1965–1968), and a close associate of Marion Milner.

Winnicott is best known for his ideas on the true self and false self, the "good enough" parent, and the transitional object. He wrote several books, including Playing and Reality, and over 200 papers.