The draw for the group stage was held on 6 December 2012. The 32 teams were drawn into eight groups of four. Teams from the same association could not be drawn into the same group. Each group was played on a home-and-away
round-robin basis. The winners and runners-up of each group advanced to the
round of 16. ;Tiebreakers The teams are ranked according to
points (3 points for a win, 1 point for a tie, 0 points for a loss). If tied on points, tiebreakers are applied in the following order: • Greater number of points obtained in the group matches between the teams concerned •
Goal difference resulting from the group matches between the teams concerned • Greater number of goals scored in the group matches between the teams concerned (
away goals do not apply) • Goal difference in all the group matches • Greater number of goals scored in all the group matches •
Penalty shoot-out if only two teams are involved and they are both on the field of play • Fewer score calculated according to the number of yellow and red cards received in the group matches (1 point for a single yellow card, 3 points for a red card as a consequence of two yellow cards, 3 points for a direct red card, 4 points for a yellow card followed by a direct red card) • Drawing of lots
Group A Group B ;
Tiebreakers • Al-Ettifaq are ranked ahead of Pakhtakor on head-to-head record.
Group C Group D Group E ;
Tiebreakers • Buriram United and Jiangsu Sainty are tied on head-to-head record, and so are ranked by overall goal difference.
Group F ;
Tiebreakers • Jeonbuk Hyundai Motors are ranked ahead of Urawa Red Diamonds on head-to-head record.
Group G Group H ==Knockout stage==