John Lumsden, Irish physician, founded the St. John Ambulance Brigade of Ireland (died 1944)

Sir John Lumsden was an Irish physician. He was famous for his role as Chief Medical Officer of Guinness Brewery, during which time he founded both St James's Gate F.C. and the St John Ambulance Brigade of Ireland. During the Easter Rising of 1916, he was noted for treating anyone who was wounded, regardless of which side they fought for.

St John Ambulance Ireland (SJAI), previously known as the St John Ambulance Brigade of Ireland, is a charitable voluntary organisation in Ireland. For constitutional reasons it is not a full member association of the Venerable Order of Saint John and the international St. John Ambulance movement, but rather is classed as an "associated body". The organisation is dedicated to the teaching and practice of medical first aid. It is engaged in first aid training to the public, providing first aid and ambulance cover at public events, patient transport and community services.