Speech, language and communication needs (SLCN) are prevalent among primary school-aged children. Collaboration between speech and language therapists (SLTs) and teachers is beneficial for supporting children's communication skills. The aim of this study was to investigate the needs of both professional groups and their preferences for service delivery when working with mainstream, primary school-aged children with SLCN. This study was undertaken within one education region in New South Wales, Australia, using a mixed-methods research design. In Phase 1, all teachers (schools n = 156) and all SLTs (n = 36) working within the region were invited to complete a questionnaire. Responses were obtained from 14 teachers and 6 SLTs. In Phase 2, a subsample of participants (n = 4) contributed to a focus group. Within the study sample, minimal collaborative practice was reportedly occurring. Teachers and SLTs expressed a desire for increased training and knowledge and more collaborative practice. Teachers and SLTs also expressed frustration at perceived systemic inadequacies with regard to funding, personnel and resources. Findings from this study suggest that change to service delivery needs to be considered at an individual, interpersonal and organizational level to enable better outcomes for children with SLCN and increased support for their families and the professionals who work with them.