Carlos Alberto de Oliveira Secretário (born 12 May 1970) is a Portuguese former professional footballer who played mainly as a right-back, currently a manager.

In a 17-year career, in which he appeared in 341 Primeira Liga games and scored 12 goals, he played for six clubs in his country including Porto, with which he won 16 major titles.

In the summer of 1993, Secretário joined Porto, quickly establishing himself as an undisputed starter in defense or midfield – after João Pinto's retirement, he played almost exclusively as a right-back – and helping the northerners to two leagues, one Cup and one Supercup in his first spell.

He attracted attention from Real Madrid, which signed the player in July 1996,[2] but he would encounter extreme difficulties in carving a starting niche with the Spanish club, which was aggravated with the January 1997 signing of Italian Christian Panucci;[3] in a bizarre incident in a game against Real Betis at the Santiago Bernabéu Stadium, a delay was caused by a rabbit presumably thrown into the fray from the terraces, and he was quick enough to catch it.

[5] On 14 March 2002, he was sent off for a professional foul on Emmanuel Olisadebe during a 2–1 continental home win over Panathinaikos, receiving a three-match suspension.