Urinary catheterization is one of the essential clinical skills that undergraduate nursing students are expected to acquire during their early professional education. Competent performance of this procedure requires not only theoretical knowledge but also psychomotor competence and confidence. Identifying effective teaching strategies for urinary catheterization is therefore important for improving nursing education and promoting patient safety. Although peer-assisted learning has been widely implemented in nursing education, evidence comparing structured instructional models delivered by peer educators and faculty instructors remains limited.

The purpose of this study is to evaluate the effects of peer-led training based on the Gagné Instructional Model on nursing students' urinary catheterization knowledge, skill performance, and self-efficacy. The effectiveness of peer-led Gagné-based training will be compared with faculty-led Gagné-based training and traditional demonstration-based instruction.

This study is designed as a single-center, three-arm, parallel-group randomized controlled trial. The study population will consist of first-year undergraduate nursing students enrolled in the Fundamentals of Nursing course at Maltepe University Faculty of Nursing during the 2025-2026 academic year. Eligible students who are 18 years of age or older, have not previously received formal theoretical or practical education on urinary catheterization, have no prior urinary catheterization experience in clinical practice, and provide written informed consent will be invited to participate. Participants who have previously received urinary catheterization training or clinical experience, fail to attend the educational sessions, or do not complete the study assessments will be excluded.

Sample size was calculated using G*Power 3.1 for repeated-measures ANOVA (within-between interaction). Based on an effect size of 0.25, a significance level of 0.05, statistical power of 95%, three study groups, and two measurement time points, the minimum required sample size was calculated as 66 participants. To compensate for potential attrition, 81 participants (27 per group) will be recruited.

Participants will be randomly assigned in a 1:1:1 ratio using computer-generated simple randomization to one of three study groups: (1) traditional demonstration-based instruction delivered by a faculty instructor, (2) peer-led training based on the Gagné Instructional Model, and (3) faculty-led training based on the Gagné Instructional Model. The educational content, teaching materials, training duration, simulation laboratory environment, and learning objectives will be identical across all groups. The only difference between groups will be the instructional approach and the individual delivering the training. Before the intervention, peer educators will receive standardized preparation regarding the Gagné Instructional Model to ensure consistency of instruction.

Data collection will be conducted using a pretest-posttest design. Before the intervention, participants will complete a knowledge test, a self-efficacy scale, and an affective self-assessment form. Following completion of the educational intervention, the knowledge test and self-efficacy scale will be repeated, and urinary catheterization skill performance will be evaluated using a standardized skills checklist.

Because participants and instructors cannot be blinded in educational intervention studies, assessor blinding will be implemented. Outcome assessors responsible for evaluating knowledge, self-efficacy, and urinary catheterization skill performance will remain unaware of participants' group allocation. Group assignments will also remain coded during statistical analyses to minimize assessment bias.

The findings of this study are expected to provide evidence regarding the effectiveness of Gagné model-based peer education in undergraduate nursing education and contribute to the development of evidence-based instructional strategies for teaching psychomotor nursing skills.