Main article: 2013–14 UEFA Champions League group stage
The draw for the group stage was held in Monaco on 29 August 2013. The 32 teams were allocated into four pots based on their 2013 UEFA club coefficients, with the title holders, Bayern Munich, being placed in Pot 1 automatically. They were drawn into eight groups of four, with the restriction that teams from the same association could not be drawn against each other.
In each group, teams played against each other home-and-away in a round-robin format. The match days were 17–18 September, 1–2 October, 22–23 October, 5–6 November, 26–27 November, and 10–11 December 2013. The group winners and runners-up advanced to the round of 16, while the third-placed teams entered the 2013–14 UEFA Europa League round of 32.
A total of 18 national associations were represented in the group stage. Austria Wien made their debut appearance in the group stage.
Teams that qualify for the group stage also participate in the newly formed 2013–14 UEFA Youth League, a competition available to players aged 19 or under.
Key to colours in group tables
Group winners and runners-up advanced to the round of 16
Third-placed teams entered the Europa League round of 32