Joaquín Loyo-Mayo (August 16, 1945, Veracruz – December 27, 2014, Córdoba, Veracruz) was a Mexican athlete who played amateur and professional tennis in the 1960s and 1970s.
Born in Veracruz, Mexico, Loyo-Mayo's playing career was coming to an end as the ATP Rankings were coming into being. He achieved a World No. 99 in those rankings on April 12, 1976.
He won the singles title at Cincinnati in 1967, and was a doubles finalist in Cincinnati in 1975 and 1968. He also reached the Round of 16 at Wimbledon in 1971, and the third round at the French Open and Wimbledon in 1970.
He represented Mexico in the Davis Cup, playing in 45 matches between 1964 and 1976.
He studied at the University of Southern California, earning a degree in marketing and winning the 1969 NCAA Men's Tennis Championship.
In 1989 he joined, as professional coach, Edgbaston Archery & Lawn Tennis Society in Birmingham, United Kingdom, the oldest lawn tennis club in the world.