AIM: To evaluate the effect of video-assisted self-assessment on nursing students' knowledge and skills in nasogastric catheter (NGS) insertion. BACKGROUND: Psychomotor skills are critical in nursing education, but traditional teaching methods often limit students' practice opportunities. Video-assisted learning, especially self-assessment, is an innovative approach for enhancing clinical competencies, yet its use specifically for nursing skill development is under-researched. DESIGN: Parallel-group Randomized Controlled Trial (Clinical Trials ID: NCT06494267). METHODS: This study involved 65 first-year nursing students at Atatürk University, assigned to an intervention group (video feedback for self-assessment, n = 31) and a control group (no video feedback, n = 34). Both groups received theoretical and practical NGS training. In the intervention group, students' NGS insertion performances were recorded and reviewed for self-evaluation, whereas the control group received no video feedback. Data were collected using a knowledge test, OSCE-based skill checklist and satisfaction questionnaire. Statistical analyses included t-tests and effect size calculations. RESULTS: Both groups showed significant pre-to-post-test improvements in knowledge and skills (p <
0.05). The intervention group achieved a greater increase in knowledge (mean 60.64 ± 15.53) compared with the control (57.20 ± 18.14
p = 0.417, d=0.203) and a significantly larger improvement in OSCE scores (intervention: 87.61 ± 7.25
control: 61.29 ± 17.51
p <
0.001, d=1.931). Additionally, 94.19 % of intervention group students reported that video-assisted self-assessment facilitated deficiency identification, with 93.55 % noting its support for objective evaluation. CONCLUSIONS: Video-assisted self-assessment significantly enhances NGS placement knowledge, skill performance and self-confidence, demonstrating its effectiveness for improving nursing education outcomes.