The 2019–20 UEFA Champions League group stage began on 17 September 2019 and ended on 11 December 2019. A total of 32 teams competed in the group stage to decide the 16 places in the knockout phase of the 2019–20 UEFA Champions League.

The draw for the group stage was held on 29 August 2019, 18:00 CEST, at the Grimaldi Forum in Monaco.

The 32 teams were drawn into eight groups of four, with the restriction that teams from the same association could not be drawn against each other. For the draw, the teams were seeded into four pots based on the following principles (Regulations Article 13.06):

On 17 July 2014, the UEFA emergency panel ruled that Ukrainian and Russian clubs would not be drawn against each other "until further notice" due to the political unrest between the countries.

Moreover, for associations with two or more teams, teams were paired in order to split them into two sets of four groups (A–D, E–H) for maximum television coverage. The following pairings were announced by UEFA after the group stage teams were confirmed:

On each matchday, one set of four groups played their matches on Tuesday, while the other set of four groups played their matches on Wednesday, with the two sets of groups alternating between each matchday. The fixtures were decided after the draw, using a computer draw not shown to public, with the following match sequence (Regulations Article 16.02):

There were scheduling restrictions: for example, teams from the same city (e.g. Real Madrid and Atlético Madrid) in general were not scheduled to play at home on the same matchday (to avoid them playing at home on the same day or on consecutive days, due to logistics and crowd control), and teams from "winter countries" (e.g. Russia) were not scheduled to play at home on the last matchday (due to cold weather).

The draw also established the group compositions of the UEFA Champions League Path of the 2019–20 UEFA Youth League.