Irvine Loudon (1 August 1924 – 7 January 2015) was a British doctor and a medical historian on childbirth fever and maternal mortality.
His father, Andrew Walker Buist Loudon was a general practitioner who had served in the Royal Army Medical Corps and his mother was Sarah Margaret Black (Morag), née Lees, who was a trained midwife.
After the war, he studied medicine at Queen's College, Oxford, graduating in 1951.
He received a fellowship from the Wellcome Trust, and was made an honorary fellow of Green College.
Loudon suffered from vascular dementia in his later years and died on 7 January 2015 at Wantage Community Hospital.