Mikel Ndubusi Agu (born 27 May 1993) is a Nigerian professional footballer who plays as midfielder for Portuguese side Vitória de Setúbal on loan from FC Porto.
Mikel Agu started his career with grassroots team Megapp FC in Nigeria. He took part in the 2009 Copa Coca-Cola, where he was chosen as the best player of the tournament, attracting the interest of scouts. After the tournament, Agu joined the youth academy of Porto.
Agu was first signed under the Porto-U 19 setup training with the senior team with the occasional bench appearance. His development would see him play 2 seasons for Porto B before eventually getting an opportunity to play for the first team. Agu made his debut against Gil Vicente in a 2-1 win coming as a substitute for Josué. Doing so, he became the first Nigerian to play for the club. Following his wonderful performance in Porto B, the then manager Paulo Fonseca promoted him to the main team. He would then be sent on loan to gain experience playing in the first division.