This resource introduces professional identity as a central factor in interprofessional relationships. It invites users to consider the implications of similarity and difference between professionals and how to sustain identity and practice constructively within collaborative relationships. It will help: understand the concept of professional identity and its importance in the relationship between professionals; consider similarity and difference between professionals; explore ‘models of practice’ as particular illustrations of similarity and difference; think about the benefits and challenges for interprofessional and inter-agency collaboration (IPIAC) that can result from professional difference; and reflect on how some of the challenges to models of practice and professional identity, may be met constructively.