Including people with intellectual disability in sport is a challenge for coaches and particularly the inclusion of these players alongside non-disabled peers. Drawing initially on the experiences of 47 coaches recruited through Special Olympics, a self-completed assessment tool was devised that can be used to evaluate the promotion of social inclusion within sport teams and the wider community. The emerging tool was field-tested with 389 coaches in the USA and seven European countries. The resulting 13 or 20 item scale had commendable psychometric properties both in terms of internal and test-retest reliability with evidence also for its ecological and predictive validity. As well as its use as a self-assessment tool within training courses for coaches, it also opens research opportunities into the relationship between this measure of inclusion and outcomes for both the coaches and for the players.