Having missed the first three matches of the 2015–16 season, due to a hamstring injury, Abdou made his first appearance of the season, starting the whole game, in a 3–2 loss against Barnsley on 18 August 2015. Since returning from injury, he quickly regained his first team place for the side, playing in the midfield position. It was not until on 26 September 2015 when Abdou scored his first Millwall goal, in a 3–1 win over Rochdale. Three days later on 29 September 2015, he set up a goal for Fred Onyedinma to score the club's first goal of the game, in a 2–2 draw against Wigan Athletic. However, during a 5–3 loss against Peterborough United on 3 October 2015, Abdou suffered a shoulder injury and had to be substituted; which after the match, he was sidelined for two months. It was not until on 26 December 2015 when Abdou made his return from injury, starting the whole game, in a 1–0 loss against Walsall. In a match against Port Vale on 17 January 2016, he made his 300th appearances for Millwall, as they won 3–1. He then continued to regained his first team place, playing in the midfield position since returning from injury. This last until he missed four matches, due to international commitment. Following his return, Abdou continued to regain his first team place towards the end of the season and went on to play a vital role in the League One play-offs that saw Millwall reach the final against Barnsley. During the match, he became the first Millwall player to appear for the club four times at Wembley Stadium, but the club went on lose 3–1. At the end of the 2015–16 season, he went on to make thirty–one appearances and scoring once for the side.