Tuca, born Valeniza Zagni da Silva (17 October 1944, São Paulo, Brazil - 8 May 1978, São Paulo, Brazil) was a Brazilian singer, guitarist and songwriter.

In 1957, Valeniza Zagni da Silva began to compose while studying classical music at the Conservatory of São Paulo. During the mid-sixties, she participated in several TV talent-shows while being part of the Group of Popular Music at the University of Architecture and Urbanization of São Paulo. She made her first steps as a professional, writing the music for Homem de verdade, penned by Consuelo de Castro. The song was recorded by singer Ana Lúcia in 1962.
Valeniza made ​​her singing debut in the television show Primeira Audição, produced by João Leão and Horácio Berlinck.