Background: Registered nurses have a professional responsibility to teach other nurses, health professionals and students; however, some newly qualified nurses lack confidence and preparedness for clinical teaching. Near-peer teaching, whereby senior students teach junior students from the same program, has been found to enhance medical students' knowledge and skills (including teaching), yet little is known about its influence on nursing students' clinical teaching self-efficacy, an important predictor of future teaching engagement. Aim: To determine if and how participation in near-peer teaching during clinical placement on senior (final Year 3) influenced nursing students' self-efficacy in clinical teaching. Design: A mixed methods explanatory sequential design was used, involving a quasi-experiment and interviews. Methods: Senior nursing students participated in either a near-peer teaching or traditional facilitator-led model during a two-week clinical placement in an acute care hospital. At the start and end of placement, participants completed a modified clinical teaching self-efficacy scale. Near-peer teaching participants were then interviewed. Survey responses were statistically analysed within and between participant groups. Interviews transcripts were thematically analysed with hybrid coding and integrated with quantitative results to corroborate, explain and expand results. Results: Near-peer teaching participants' (n = 33) clinical teaching self-efficacy significantly increased (p < .001) during placement; control participants had no change (n = 38; p = .73). All interviewed participants (n = 12) reported increased clinical teaching confidence. Having prior peer teaching experience, repeatedly engaging in teaching, observing others teach and receiving feedback and encouragement during placement strengthened participants' clinical teaching self-efficacy and willingness to teach in the future. Conclusions: Near-peer teaching during clinical placement strengthens final year nursing students' clinical teaching self-efficacy and supports practice-readiness – findings not previously reported in the literature. University faculty from health disciplines should consider near-peer teaching integration to prepare students for essential teaching roles in healthcare contexts.