The 1973 New South Wales Rugby Football League premiership was the sixty-sixth season of the rugby league competition based in Sydney. Twelve district clubs from across the city, including six foundation clubs, competed for the J.J. Giltinan Shield and WD & HO Wills Cup during the season, which culminated in a grand final between Manly-Warringah and Cronulla-Sutherland. This season also saw the introduction of an Under-23s competition to replace the former “Third Grade” as well as a five-team finals series (rather than the previous four).