 Mousinho missed the start of the 2011 – 12 season due to suffering a calf injury during pre-season, subsequently missing Stevenage's first three games of the campaign. He returned to first-team action on 16 August 2011, starting in a 3 – 1 away victory against Bournemouth, scoring Stevenage's second goal of the game from the penalty spot. Mousinho's second goal of the season came in Stevenage's 5 – 1 win against Sheffield Wednesday at Broadhall Way, beating defender Rob Jones for pace before driving a shot from 20 yards past goalkeeper Richard O 'Donnell. He injured a metatarsal bone in his right foot in Stevenage's 1 – 0 away victory against Hartlepool United in the FA Cup on 12 November 2011, and was subsequently ruled out of first-team action for six weeks. Mousinho suffered another setback in January, when scans revealed further damage to the metatarsal bone. After a brief substitute appearance in Stevenage's reserve game against Southend United in early April 2012, Mousinho returned to first-team action on 14 April 2012, coming on as a late substitute in the club's 6 – 0 away victory at Yeovil Town. In the club's next match, a "vital" game against fellow play-off contenders Carlisle United, Mousinho came on as a substitute in the 73rd minute and scored the winning goal three minutes later as Stevenage ran out 1 – 0 winners. He made 23 appearances during an injury-hit season, scoring three goals. Just three days after Stevenage's play-off semi-final defeat, on 17 May 2012, Stevenage announced that Mousinho had turned down an improved contract and was leaving the club after two years.
