In December 2011, Mensah was named to the Ghana's squad for the 2012 Africa Cup of Nations, which was co-hosted by Equatorial Guinea and Gabon. In a match against Botswana on 24 January 2012, he scored his first goal of the tournament, but was sent–off in the 66th minutes, in a 1–0 win. After serving a one match suspension, he didn't return until on 5 February 2012 when Mensah scored his second goal of the tournament, in a 2–1 win against Tunisia. He went on to play three times in tournament, as Ghana finished fourth place following a 2–0 defeat to Mali. Despite this, Mensah was included in the Confederation of African Football All-Stars team for the 2012 Africa Cup of Nations. It was not until on 15 August 2012 when he made his last Ghana appearance and played 45 minutes, in a 1–1 draw against China.