Background; Organizations are under obligation to respond wisely and creatively to the challenges of the modern workplace due to its fast pace, frequent and disruptive change, and complexity. Furthermore, there is a growing demand for manager-led coaching worldwide since it is considered one of the most powerful development activities, cost-efficient, and successful than hiring an external coach. Recently, nurse managers mastering coaching and interpersonal skills considered an advantage for prestigious health organizations. This paper aimed to examine the effect of coaching program on nurse managers’ interpersonal skills and nurses’ motivation. Methods: A quasi-experimental design was utilized. The study was conducted from July 2021 to March 2022, at a private hospital in Cairo, consists of eight floors, 300 bed capacity, covered with different medical specialties and units. Convenient sample of (36) nurse managers’ and (154) staff nurses were participated in this study. Four tools were utilized; “Nurse Manager interpersonal skills observational checklist, ‘coaching observational checklist, Nurses’ motivation questionnaire, and Nurse Managers’ coaching knowledge test”. Results: a statistically significant increase in total observed interpersonal skills mean scores during different periods of observation (f=166.800; p=.0001*), a significant increase in total observed coaching skills mean scores between rehearsal and execution (t=9.153; p=.0001*), a statistically significant increase in mean scores of nurses’ motivation between pre & post assessment (t=26.94; p=.0001*), and a significant increase in mean scores of nurse managers' coaching knowledge was observed between the pre- and post-program implementation (t=30.6; p=.0001*). Additionally, a high statistically significant correlation was identified between coaching skills dimensions and observed interpersonal skills, during different periods of observation (R=0.71, P=.0001*). Conclusion: Implementation of the coaching training program for nurse managers has been demonstrated to have a positive effect on nurse managers’ coaching knowledge, coaching and interpersonal skills, and staff nurses’ motivation levels in the clinical settings.