The 2015–16 season was Charlton Athletic's 94th season in their existence and 4th consecutive season in the second tier of the English football league system. Along with competing in the Championship, the club also participated in the FA Cup and League Cup. The season covered the period from 1 July 2015 to 30 June 2016.
On 18 May 2015, Charlton Athletic announced they would face Welling United in a pre-season friendly on 11 July 2015.[57] On 29 May 2015, the club announced three XI pre-season friendlies.[58] On 1 June 2015, the club announced they will head to Belgium on a pre-season tour and play two games. One confirmed is against Sint Truiden on 18 July 2015.[59] Two days later, Southend United and Dagenham & Redbridge was added to the schedule.[60] On 4 June 2015, a friendly against Genk was announced.[61] Two days later, two home pre-season friendlies were announced.[62] On 12 July 2015, Charlton Athletic announced a replacement friendly against Bolton Wanderers due to A.C. ChievoVerona cancelling friendlies against both teams.[63]
^Kashi was born in Aubervilliers, France, but also qualified to represent Algeria internationally and made his international debut for Algeria in January 2015.
^Harriott was born in Croydon, England, and represented them at U-19 level, but also qualified to represent Guyana and Jamaica internationally and would make his international debut for Guyana in March 2019.
^Vetokele was born in Ostend, Belgium, and represented them at U-17, U-18, U-19, and U-21 level, but also qualified to represent Angola internationally and made his international debut for Angola in 2014.
^Bergdich was born in Compiègne, France, but also qualified to represent Morocco internationally and represented them at U-23 level before making his international debut for Morocco in 2012.
^Fox was born in Chelmsford, England, but also qualified to represent Wales internationally and represented them at U-21 level.
^Poyet was born in Zaragoza, Spain, but was raised in England from the age of 2 and also qualified to represent Uruguay internationally through his father. He represented England at U-16 and U-17 level and Uruguay at U-20 level.
^Church was born in High Wycombe, England, but also qualified to represent Wales through his grandparents and represented them at U-21 level before making his international debut for Wales in May 2009.
^Daniel was born in Lambeth, England, but also qualified to represent Guyana internationally and represented them at U-23 level before making his international debut for Guyana in June 2015.
^Etheridge was born in Enfield, England, and represented them at U-16 level, but also qualified to represent the Philippines through his mother and made his international debut for the Philippines in May 2008.
^Wiggins was born in Hillingdon, England, but also qualified to represent Wales internationally and represented them at U-17, U-19, and U-21 level.
^Ansah was born in Bexley, England, and represented them at U-16 and U-17 level, but also qualified to represent Ghana internationally and has confirmed his international allegiance to them.