Interprofessional collaboration (IPC) is widely promoted to improve support for youth with complex and multiple needs, yet fragmented and poorly coordinated services persist. This scoping review seeks to explore how IPC has been conceptualised in social welfare services, describe factors that shape collaborative processes, and identify areas where further research is needed. Informed by complexity theory, IPC is conceptualised as a dynamic, adaptive process arising from non-linear interactions among professionals, youths, and families. A comprehensive search of five databases yielded 785 records; twenty-four studies met the inclusion criteria. Data were charted and thematically analysed, generating five themes: (1) General Characteristics, (2) The Construct of Interprofessional Collaboration, (3) Barriers and Drivers of Interprofessional Collaboration, (4) User Participation, and (5) Outcome. Findings indicate that the literature foregrounds drivers and barriers primarily from professional perspectives while offering limited clarity on IPC’s core definitions and intended outcomes. IPC is frequently treated as a ‘black box’, marked by heterogeneous terminology and uneven empirical grounding. Future research should move beyond descriptive accounts and develop approaches that foreground youth perspectives while capturing the evolving, relational dynamics of IPC.