The 2002–03 UEFA Champions League first group stage matches took place between 17 September and 13 November 2002. The draw for the group stage was made on 29 August 2002 in Monaco. The group stage featured the 16 automatic qualifiers and the 16 winners of the third qualifying round. Each team was drawn into one of eight groups but avoided teams from their own country. All four teams in the group played home and away matches against each other to determine the winner and runner-up in the group. At the completion of the group stage, the top two teams in each group advanced to play in a second group stage, while the third-placed teams dropped down to the UEFA Cup.

Seeding

Seeding was determined by the UEFA coefficients. Clubs from the same association were paired up to split the matchdays between Tuesday and Wednesday. Clubs with the same pairing letter would play on different days, ensuring that teams from the same city (e.g. Milan and Internazionale, who also share a stadium) did not play on the same day.

Tie-breaking criteria

Based on Article 7.06 in the UEFA regulations, if two or more teams are equal on points on completion of the group matches, the following criteria will be applied to determine the rankings:

Groups

Times are CET/CEST, as listed by UEFA (local times are in parentheses).

Group A

Group B

Group C

Group D

Group E

Group F

1 Maccabi Haifa played their home group matches at the GSP Stadium in Nicosia, Cyprus after UEFA banned international matches from being played in Israel.

Group G

Group H