The Lady Margaret Boat Club is the rowing club for members of St John's College, Cambridge, England. The club is named after Lady Margaret Beaufort, founder of the College.

St John's College, formally the College of St John the Evangelist in the University of Cambridge, is a constituent college of the University of Cambridge, founded by the Tudor matriarch Lady Margaret Beaufort. In constitutional terms, the college is a charitable corporation established by a charter dated 9 April 1511. The aims of the college, as specified by its statutes, are the promotion of education, religion, learning and research. It is one of the largest Oxbridge colleges in terms of student numbers. For 2022, St John's was ranked 6th of 29 colleges in the Tompkins Table with over 35 per cent of its students earning first-class honours. It is the second wealthiest college in Oxford and Cambridge, after its neighbour Trinity College, Cambridge.