Australian community pharmacies offer a range of professional pharmacy services (PPS) which include Home Medicines Review (HMR) and the Diabetes Medication Assistance Service (DMAS). The extent of interaction and collaboration between general practitioners (GPs) and pharmacists in the context of these services is unknown. Therefore, the aim of this study was to investigate (1) the nature and extent of interactions between GPs and community pharmacists and; (2) the factors that influence these interactions in the context of PPS. Individual semi-structured face-to-face and telephone interviews were conducted with a purposive sample of 15 GPs and 15 pharmacists in rural and metropolitan areas of New South Wales, Australia. The results indicated that involvement in PPS resulted in a perceived increase in the level of interactions between the pharmacist and GP. Factors found which may influence collaborative behaviour in PPS include interactional, practitioner and environmental determinants. These factors are in line with what has previously been reported however, facilitators of collaboration in the primary care, PPS context included additional environmental factors such as the presence of rules and protocols, interprofessional continuing education and the availability of adequate remuneration. Attention to these environmental factors as well as the more established interactional and practitioner determinants will improve collaboration in PPS.