Background: Rising antimicrobial resistance (AMR) in primary care is a growing concern and a threat to community health. The rise of AMR can be slowed down if general practitioners (GPs) and community pharmacists (CPs) could work as a team to implement antimicrobial stewardship (AMS) programs for optimal use of antimicrobial(s). However, the evidence supporting a GP pharmacist collaborative AMS implementation model (GPPAS) in primary care remains limited. Aim: With an aim to design a GPPAS model in Australia, this paper outlines how this model will be developed. Methods: This exploratory study undertakes a systematic review, a scoping review, nationwide surveys, and qualitative interviews to design the model. Medical Research Council (MRC) framework and Normalization Process Theory are utilized as guides. Reviews will identify the list of effective GPPAS interventions. Two AMS surveys and paired interviews of GPs and CPs across Australia will explore their convergent and divergent views about the GPPAS interventions, attitudes towards collaboration in AMS and the perceived challenges of implementing GPPAS interventions. Systems Engineering Initiative for Patient Safety (SEIPS 2.0) model and factor analyses will guide the structure of GPPAS model through identifying the determinants of GPPAS uptake. The implementable GPPAS strategies will be selected based on empirical feasibility assessment by AMS stakeholders using the APEASE (Affordability, Practicability, Effectiveness and cost-effectiveness, Acceptability, Side-effects and safety, Equity) criteria. Discussion: The GPPAS model might have potential implications to inform how to better involve GPs and CPs in AMS, and, to improve collaborative services to optimize antimicrobial use and reduce AMR in primary care.