INTRODUCTION: In settings where the private sector constitutes a larger part of the health system, profit-gathering can take primacy over patients' well-being. In their interactions with pharmaceutical companies, private general practitioners (GPs) can experience the conflict of interest (COI), a situation whereby the impartiality of GPs' professional decision making may be influenced by secondary interests such as financial gains from prescribing specific pharmaceutical brands. METHODS AND ANALYSIS: This study is a randomised controlled trial to assess the impact of a multifaceted intervention on GPs' medical practice. The study sample consists of 419 registered GPs who own/work in private clinics and will be randomly assigned to intervention and control groups. The intervention group GPs will be exposed to emotive and educational seminars on medical ethics, whereas control group GPs will be given seminars on general medical topics. The primary outcome measure will be GPs' prescribing practices, whereas the secondary outcome measures will be their knowledge and attitudes regarding COI that arises from pharmaceutical incentivisation. In addition to a novel standardised pharmaceutical representatives (SPSR) method, in which field researchers will simulate pharmaceutical marketing with GPs, presurvey and postsurvey, and qualitative interviewing will be performed to collect data on GPs' knowledge, attitudes and practices in relation to COI linked with pharmaceutical incentives. Univariate and multivariate statistical analyses will be performed to measure a change in GPs' knowledge, attitudes and practices, while qualitative analysis will add to our understanding of the quantitative SPSR data. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Pakistan National Bioethics Committee (# 4-87/NBC-582/21/1364), the Aga Khan University (# 2020-4759-1129) and the London School of Hygiene and Tropical Medicine (# 26506). We will release results within 6-9 months of the study's completion. TRIAL REGISTRATION NUMBER: ISRCTN12294839.