Abstract Background Inappropriately using proton pump inhibitors (PPI) is associated with severe adverse drug reactions and may have major consequences on healthcare costs. Deprescribing (the process by which a healthcare professional supervises the withdrawal of an inappropriate medication, to manage polypharmacy and improve outcomes) should be considered when an inappropriate PPI prescription is identified. Deprescribing interventions directed solely to prescribers have limited efficacy and are rarely targeted to patients. The aim of this trial is to assess the efficacy of a multi-faceted intervention with patients and general practitioners (GPs) to deprescribe PPI. Methods We will conduct a pragmatic , cluster-randomized, population-based, controlled trial in two regions of Western France. GPs with practices with over 100 patients, and their adult patient to whom over 300 defined daily doses (DDD) of PPIs have been dispensed in the year before baseline will be included. A total of 1300 GPs and 33,000 patients will be cluster-randomized by GPs practices. Three arms will be compared: i) a multi-faceted intervention associating a) a patient education brochure about PPI deprescribing sent directly to patients (the brochure was designed using a mixed-methods study), and b) a personalized letter with the Bruyere’s PPI deprescribing algorithm sent to their respective GPs, or ii) a single intervention where only the GPs received the letter and algorithm, or iii) no intervention. The primary outcome will be PPI deprescribing, defined as the proportion of patients achieving at least a 50% decrease in the amount of PPI dispensed to them (DDD/year) at 12 months compared to baseline. Secondary outcomes will include incremental cost-utility ratio (using EQ-5D-5L scale and National Health Insurance’s database), acid rebound (using the Gastroesophageal Reflux Disease Impact Scale), and the patients’ attitudes towards deprescribing (using the French rPATD). Discussion Based on previous trials, we anticipate more than 10% “successful PPI deprescribing” in the multi-faceted intervention compared to the single intervention on GPs and the control arm . The study has been funded through a national grant and will be launched in autumn 2020, for early results by the end of 2022. Trial registration Clinicaltrials.gov NCT04255823 ; first registered on February 5, 2020.