Benvenuto Martins Nunes (born June 27, 1913) is a former Olympic freestyle and backstroke swimmer from Brazil, who participated at two Summer Olympics for his native country.
At the 1932 Summer Olympics in Los Angeles, he swam the 4×200-metre freestyle, finishing 7th in the final, along with Manuel Silva, Isaac Morais 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.