The 2012–13 Mohun Bagan FC season was the club's 6th season in I-League and 123rd season since its establishment in 1889. The team finished runners-up in the Calcutta Football League and a dismal tenth in the I-League. They were crowned Champions in the Airlines Cup after Mohammedan refused to play the finals and gave a walkover. Mohun Bagan crashed out in the group stage of the Federation Cup and were defeated by arch rivals East Bengal in the semi-finals of the IFA Shield.
On 29 December 2012, Mohun Bagan were barred from competing in the I-League for 2 years following a decision taken by the I-League core committee. All their results in the I-League were declared null and void and all their remaining fixtures were cancelled.[1] The suspension came because Mohun Bagan had refused to take the field in the second half of the match against East Bengal on 9 December 2012, citing crowd violence and unsuitable atmosphere for the continuation of the match.[2]
However, on 15 January 2013, Mohun Bagan appealed against the decision to ban them from the I-League and were reinstated, but were fined a hefty amount, there officials were suspended from all AIFF meetings for one year and the team would start on 0 points and would play out only the remaining 16 fixtures in the league. This however, did not affect their win–loss and goal difference record in the table.[3]
^On 29 December 2012, Mohun Bagan failed to turn up in the second half of the match against East Bengal due to crowd trouble; their record was expunged, with their remaining fixtures scratched, and they were banned from the I-League for until 2015 by the I-League core committee.[34] On 15 January 2013, Mohun Bagan appealed the decision to ban them from the league and were reinstated, but would start on 0 points.[35]
Mohun Bagan were declared winners of the 2012 Airlines Cup after Mohammedan refused to play the final due to excessive rescheduling of the final match. The tournament committee took the decision of giving a walkover to Mohun Bagan.[36]
Odafa Onyeka Okolie was suspended for one match in addition to the two match suspension he received as a result of the direct red card he picked up in the match against East Bengal on 9 December 2012.[37]