Guillermo Martínez is the name of:
Guillermo Martínez (baseball) (born 1984), American baseball coach Guillermo Martínez Ayala (born 1995), Mexican football player Guillermo Martínez (javelin thrower) (born 1981), Cuban javelin thrower Guillermo Martínez (sport shooter) (born 1930), Colombian sport shooter Guillermo Martínez (volleyball) (born 1969), Argentine volleyball player Guillermo Martínez (writer) (born 1962), Argentine novelist and short story writer Guillermo Martínez Casañ (born 1955), Spanish politician Guillermo Ortiz Martínez (born 1948), Mexican economist and politician Guillermo Zúñiga Martínez (1942–2015), Mexican politician