This study documented the perceived needs of therapists, specialists, and managers who work with children with intellectual disabilities (ID) and/or autism spectrum disorders (ASD) and concurrent problem behaviours (PBs). Seventy-five respondents from specialized PB and early childhood programs within eight public rehabilitation centres were surveyed. They were asked to describe current practices and perceived needs in terms of assessment, intervention, and training with respect to the target population. Overall, the perceptions of staff were consistent with the results of previous studies examining families' perspectives. Salient themes include the need for specialized assessments for PBs in young children, collaboration between multiple service providers and families, and additional staff training in child development and interventions for PBs. These findings underscore the importance of offering diversified services adapted to the needs of children with PBs, their families, and their service providers.