Nancy Vallecilla (born November 24, 1957) is a retired female athlete from Ecuador, who competed in the hurdling events and the heptathlon. She represented her native country twice at the Summer Olympics: 1980 and 1988. Vallecilla finished fifth in the pentathlon at the 1979 Pan American Games as well as fourth (1987) and seventh (1979) in the 100 metres hurdles at the Pan American Games.