Serge-Junior Martinsson Ngouali (born 23 January 1992), commonly known simply as Junior, is a professional footballer who plays as a midfielder for Allsvenskan club IF Brommapojkarna.

Living in the suburb of Hammarkullen, he started to play football at local clubs Gunnilse IS and Västra Frölunda IF.

[4] Martinsson Ngouali also featured in both legs against the Serie A side Torino as Brommapojkarna got knocked out from the 2014–15 UEFA Europa League third qualifying round.

In the first leg on home ground, he got fouled inside the penalty area by defender Giuseppe Vives who received a red card from the referee.

[10] Midway through his first season at Hammarby, Junior received much praise from the club's director of football Jesper Jansson, who complimented him as a "real class player" with a strong defensive game and great ability to cover big surfaces on the pitch.

[11] On 21 August, in a 3–0 away win against Örebro SK, Martinsson Ngouali attracted a serious thigh injury that kept him out of play for almost two months.

[19] On 15 February 2021, Martinsson Ngouali signed a one-and-a-half-year contract with Prva HNL club HNK Gorica, linking up with Jiloan Hamad, his former teammate from Hammarby.

[22] In the summer of 2016, he was approached by the Gabonese national football team when manager José Antonio Camacho invited him to a training camp.