Marquez (born March 29, 1938), better known as Alfonso "Boy" Marquez, is a Filipino former basketball player and coach.
Marquez was born in Zamboanga City, Philippines.
A product of Ateneo de Zamboanga High School team and the University of Visayas, he came to Manila joining the Ysmael Steel Admirals in 1958.
He won six championships as a part of the Ysmael Steel squad.
An all-around player, he could play the center, forward and guard positions.
Marquez also appeared at the Olympic Games as a member of the country's national basketball team.
At the 1968 Mexico Olympics, Marquez and another Hall of Famer Ed Ocampo took turns in shackling Shin Dong-pa as the Philippines beat South Korea, 63-60.
Marquez shot 18 points and Shin, 16.
He later played for MERALCO and Mariwasa during the 1970s in the Manila Industrial and Commercial Athletic Association.