John "na Seamer" Burke, Baron Leitrim (Irish: Seán mac an Iarla a Búrc; /ˈliːtrəm/; LEE-trəm; died 1583), also known as John of the Shamrocks, was one of the notorious half-brothers called the meic an Iarla ('sons of the earl'), whose conflicts with each other and their father, Richard Burke, 2nd Earl of Clanricarde, caused devastation to south Connacht several times between the late 1560s and early 1580s.