IntroductionIt is unknown whether interprofessional identity is able to explain interprofessional behaviours. Extended professional identity theory provides clues by combining two psychological identity approaches. The aim of this study is to investigate whether interprofessional identity is a source for intrinsic motivation towards interprofessional collaboration related to wider group membership.MethodsParticipants of this double‐blinded study were 47 dentistry and 41 dental hygiene students (86.3% response) without interprofessional education (IPE) experience. Group productivity was used as indicator of group effort and equal communication as indication for interprofessional direction. The extended professional identity scale (EPIS) was used to measure interprofessional identity eight weeks prior to a mandatory IPE course. Based on EPIS levels, students were assigned to a low or high interprofessional identity group condition. Subsequently, 12 interprofessional teams (four to five members) were randomly composed per condition. Each group received eight problems (regarding roles, responsibilities and collaborative practice) for which they were expected to provide up to 10 solutions. Six trained psychologists rated the validity of solutions after which the percentage of solutions per group was calculated. Additionally, the psychologists rated interprofessional direction by observing team communication (asking questions, topic control, prosocial formulations, and speech frequency) during the second group meeting.ResultsNo interprofessional identity differences were found with regard to gender and profession. The mean difference between groups with low versus high interprofessional identity was 0.5 (M = 3.4; SD = 0.5 and M = 3.9, SD = 0.4, respectively), t = −5.880, p < 0.001. Groups with high identity generated more solutions compared to low identity groups (91.5% vs. 86.4%), t = −2938, p = 0.004. The correlation between individual interprofessional identity and group effort was significant, r = 0.22, p = 0.036. Groups with high identity showed more interprofessional direction, t = −2.160, p = 0.034.DiscussionInterprofessional identity has a positive effect on congruent interprofessional behaviours after 10 weeks. More research is required to understand interprofessional identity in relation to performance in education and work.