Introduction Antimicrobial resistance has been described as a global crisis—more prudent prescribing is part of the solution. Behaviour change interventions are needed to improve prescribing practice. Presently, the literature documents that context impacts on prescribing decisions, yet insufficient evidence exists to enable researchers and policymakers to determine how local tailoring should take place. Doctors in training are an important group to study, being numerically the largest group of prescribers in UK hospitals. Unfortunately very few interventions specifically targeted this group.

Methods and analysis Our project aims to understand how interventions to change antimicrobial prescribing behaviours of doctors in training produce their effects. We will recruit a project stakeholder group to advise us throughout. We will synthesise the literature using the realist review approach—a form of theory-driven interpretive systematic review approach often used to make sense of complex interventions. Interventions to improve antimicrobial prescribing behaviours are complex—they are context dependent, have long implementation chains, multiple non-linear interactions, emergence and depend on human agency. Our review will iteratively progress through 5 steps: step 1—Locate existing theories; step 2—Search for evidence; step 3—Article selection; step 4—Extracting and organising data; and step 5—Synthesising the evidence and drawing conclusions. Data analysis will use a realist logic of analysis to describe and explain what works, for whom, in what circumstances, in what respects, how and why to improve antimicrobial prescribing behaviour of doctors in training.

Ethics and dissemination Ethical approval was not required for our review. Our dissemination strategy will be participatory and involve input from our stakeholder group. Tailored project outputs will be targeted at 3 audiences: (1) doctors in training; (2) clinical supervisors/trainers and medical educators; and (3) policy, decision makers, regulators and royal societies.