BackgroundReflection is a core competency in geriatric nursing, and reflective learning is an effective approach in nursing education and pracice. An internship program is a transition course that enhances the knowledge, skills, and attitudes of aspiring nursing students in real clinical work. In geriatric clinical setting, nursing internship students require a broad understanding of professional competency that integrates reflective learning with clinical practice to deal with geriatric patient problems and equip them with the knowledge, attitudes, and skills needed to provide quality of care. However, there is a lack of studies examining the effect of holistic reflective learning on professional competency development among nursing internship students in geriatric settings.AimThis study aimed to investigate the effect of professional holistic reflective learning on professional competency development among nursing internship students caring for hospitalized older adults in medical-surgica wards.DesignThis study employed a quasi-experimental pretest–posttest design, where 160 participants were grouped into control and intervention groups. This study was conducted at two nursing schools under the Mashhad University of Medical Sciences in Iran in 2020. Baseline information was collected from both groups, followed by a pretest and follow-up assessment. The intervention group received a Blended Professional Holistic Reflective learning program, while the control group received conventional learning(undertaking professional clinical practice as a usual treatment and submitted reflective logbooks),, which included standard lectures and group discussions.MethodsParticipants were selected based on specific inclusion and exclusion criteria. The selection process was non-randomized and unblinded. The participants were equally divided, with 80 in the control group and 80 in the intervention group. Baseline data, including demographic characteristics, were collected. Pretest data were collected for both groups using the Geriatric Nursing-Specific Mini-CEX (GN-Specific Mini-Clinical Evaluation Exercise), an instrument designed to assess nursing students' professional competency in geriatric nursing practice. The intervention was delivered through a combination of in-person and online sessions over four mounts. Posttest data and follow-up, were collected similarly to the pretest. Data were analyzed using SPSS version 22, and potential confounding variables were controlled for in the analysis.ResultsThe study included a total of 160 nursing internship students, with no exclusions. At baseline, no significant differences were observed between the intervention and control groups in terms of professional competency (PC) and its dimensions, except for age, which was adjusted as a covariate in the analyses. The intervention group showed a significant improvement in PC and its various domains (communication skills, physical examination, clinical judgment, health education, professionalism, and organizational efficacy) over time. The Generalized Estimating Equation (GEE) analysis confirmed significant interaction effects between time and group for all PC dimensions (p < 0.05). Post-test comparisons revealed that the intervention group scored 2.4 points higher than the control group in overall PC (p < 0.001), with sustained improvements in the follow-up phase. Significant within-group improvements were also found across all PC dimensions for both groups from pre-test to follow-up (p < 0.05).ConclusionsThe study found that the professional holistic reflective learning program was effective in developing professional competency among nursing internship students. The blended teaching–learning approach (face-to-face and online) during workshops and geriatric clinical practice is a practical, cost-effective, and time-efficient learning program during students' clinical practice in geriatric settings. Nurse educators are recommended to implement holistic reflective learning during clinical education.