Adnan Januzaj (born 5 February 1995) is a Belgian professional footballer who plays as a winger for La Liga club Sevilla.

Born and raised in Brussels, Januzaj began his career with Anderlecht before joining Manchester United in 2011 at the age of 16. Januzaj broke into the Manchester United first-team under manager David Moyes during the 2013–14 season, but struggled for opportunities under Moyes' successors Louis van Gaal and José Mourinho, and had loan spells at Borussia Dortmund and Sunderland before joining Real Sociedad in July 2017.

Januzaj made his full international debut in 2014 and later that year played for Belgium at the FIFA World Cup in 2014 and 2018, reaching the semi-finals of the latter tournament.

Januzaj began his football career with FC Brussels but joined Anderlecht as a ten-year-old in 2005. He left Anderlecht for Manchester United at the age of 16 in March 2011, after impressing in a skills session in Brussels.

Towards the end of the 2012–13 season, United manager Sir Alex Ferguson promoted Januzaj to the first-team and he was registered with the number 44 jersey; he did not feature in the remainder of the season, but he was an unused substitute in the final game of the season away to West Bromwich Albion. For his performances during the season, Januzaj won the 2013 Denzil Haroun Reserve Team Player of the Year award. He was included in the first-team squad for the 2013–14 pre-season tour of Asia and scored in the final game of the tour against Hong Kong side Kitchee five minutes after being substituted on. He also started in Rio Ferdinand's testimonial; United lost 3–1 to Sevilla, but Januzaj provided the assist for United's only goal.

"It's a great thrill to be able to sign for Manchester United. Since arriving here, I have always felt like this was the right club for me. This season has been great for me – going on the pre-season tour, making my debut in the Community Shield win at Wembley and then breaking into the team at Sunderland – it's like a dream. I want to work hard now and establish myself as a Manchester United player."

Januzaj made his competitive debut for Manchester United against Wigan Athletic on 11 August 2013 in the Community Shield, coming on for Robin van Persie with six minutes left to play. He made his Premier League debut a month later, coming on as a 68th-minute substitute for Ashley Young in a 2–0 home win over Crystal Palace on 14 September. On 5 October 2013, in what was his first start for the club, Januzaj scored twice as United came from behind to claim a 2–1 victory away to Sunderland. In an effort to stave off interest from other clubs, who could have signed Januzaj for "minimal compensation" on the expiry of his existing contract in June 2014, Manchester United signed Januzaj to a new five-year contract on 19 October 2013. On 3 December 2013, he was nominated for the BBC Young Sports Personality of the Year; at the time of his nomination, he had played in ten games for Manchester United.

Januzaj was left out of Manchester United's initial squad for the UEFA Champions League when it was registered in September 2013, which came as a surprise to some members of the media after his impressive start to the season. Manager David Moyes later explained this was a tactical decision to allow the club to register an additional player for the competition; as Januzaj had not been with the club long enough to be eligible for the 'List B' squad, which for 2013–14 included any player born after 1 January 1992 who had been eligible to play for the club for at least two years, he would have had to be registered as one of only 25 'List A' players, taking up a space that could have been used by another player. By waiting until 7 October 2013 to register Januzaj, he became eligible as a List B player, but this meant that he could not be selected for the club's first two matches in the competition, at home to Bayer Leverkusen and away to Shakhtar Donetsk. Despite being available from the third game of the tournament, at home to Real Sociedad, Januzaj was left out of both games against the Spanish club and the return match against Bayer Leverkusen. He made his Champions League debut at home to Shakhtar Donetsk on 10 December 2013.