The First and Third Trinity Boat Club is the rowing club of Trinity College in Cambridge, England. The club formally came into existence in 1946 when the First Trinity Boat Club and the Third Trinity Boat Club merged, although the two clubs had been rowing together for several years before that date. The first boat club associated with Trinity was formed in 1825 and came to be known as First Trinity in 1833 when the Third Trinity Boat Club was formed. Membership of Third Trinity was originally confined to Old Etonians and Old Westminsters. Members of Third Trinity were allowed also to be members of First or Second Trinity and often were.

Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any Oxbridge college. Trinity performs exceptionally as measured by the Tompkins Table, coming top from 2011 to 2017. Trinity was the top-performing college for the 2020–21 undergraduate exams, obtaining the highest percentage of good honours.