ObjectiveThe study objective is to determine the effectiveness of the suicide prevention program (SPP) on knowledge, attitude, and gatekeeper behaviour among teachers of Pre University colleges. MethodThis is a randomized controlled study, divided into two phases with assessments at baseline, one month, three months, and six months. A descriptive cross-sectional survey will be conducted in Phase-I among all teachers of first-year Pre-University courses of Udupi using the Literacy of Suicide Scale (LOSS), Attitude Towards Suicide Prevention (ATSP) scale, and Gatekeeper Behavior Scale (GBS). The participants who score below 75 % in the knowledge domain in Phase I will be recruited into Phase II. Pre-University colleges will be assigned to intervention and control groups by cluster randomization. Based on the types of colleges (Unaided, aided, and government), a proportionate sampling technique will be adopted to recruit 62 participants into each group. A ten-hour workshop on suicide prevention program (SPP) will be conducted for the intervention group. An information booklet on suicide prevention will be provided to the control group after the third follow-up (six months). The data will be analyzed statistically. Expected resultsIf the study results demonstrate statistical superiority of the intervention group over the control group in improving the knowledge, attitude, and gatekeeper behaviour on suicide prevention, it could enable the Pre-University teachers to implement the SPP. ConclusionThe present study results may support the implementation of the SPP. Trial registration numberCTRI/2022/09/045819.