Cacequi is a municipality in the state of Rio Grande do Sul, Brazil, 407 km from Porto Alegre.

The town is situated at an elevation of 103 m, with an area of 2,441 km2, and is known as the capital of the watermelon.

Its Patron Saint is Our Lady of Victory.

Its name derives from the Tupi language: Cacequi, (bean's water) from cumandá, bean; í, water.

The mayor of the city is Francisco Fonseca Franco.