The 1977 Brabham BT45B was a Formula One car designed by Gordon Murray and raced by the Brabham team during the 1977 season. An evolution of the original BT45, it featured an Alfa Romeo flat-12 engine and was known for its distinctive aerodynamic design. Driven by notable drivers such as Carlos Pace and John Watson, the BT45B had a competitive but challenging season, scoring several points finishes and achieving a podium at the Monaco Grand Prix. Despite reliability issues and stiff competition from rivals like Ferrari and Ferrari-powered cars, the BT45B contributed to Brabham's presence in the midfield battles of the late 1970s F1 scene.