Benevenuto Martins Nuñes (born 27 June 1913, date of death unknown) was an Olympic freestyle and backstroke swimmer from Brazil, who participated at two Summer Olympics for his native country. At the in Los Angeles, he swam the 4×200-metre freestyle, finishing 7th in the final, along with Manuel Silva, Isaac Moraes and Manoel Villar. He also swam the 100-metre backstroke, not reaching the finals. At the 1936 Summer Olympics in Berlin, he swam the 100-metre backstroke, not reaching the finals.