Background: Leadership style of nurse managers can effectively motivate and mobilize them and enhance staff nurses to accomplish positive outcomes among staff nurses. Aim of the study: To assess the effect of educational program about adaptive leadership for nurse managers on staff nurses' outcomes. Study design: A quasi-experimental design. Setting: The study was conducted in all inpatient units at Benha University Hospital. Study subjects: Consisted of two groups: nurses managers (130) and staff nurses group (326). Tools of data collection: Three tools were used; Tool (I) Adaptive leadership Knowledge Questionnaire, Tool (II) Adaptive Leadership Self Report Questionnaire and Tool (III) Staff Nurses' Outcomes Questionnaire. Results: More than half (60.8%) of nurse managers had inadequate knowledge regarding adaptive leadership at pre-program phase, which improved to the majority (84.6%) of them had adequate knowledge at post-program phase with slightly decrease to be 78.5% at follow up phase. More than three fifths (67.7%) of nurse managers had unsatisfactory performance regarding adaptive leadership approaches at pre-program which improved to be the majority (81.5%) of them had satisfactory performance at immediate post program with slightly decreased to be more than three-quarters (76.9%) at follow up program phase. The highest percent (64.1 % & 59.8%) of staff nurses had high outcomes level at immediate post program and follow up phases respectively compared with one fifths (36.8%) of staff nurses had low level at pre-program phase. Conclusion: There were a highly statistically significant positive correlation between nurse managers' total knowledge and performance regarding adaptive leadership and staff nurses' outcomes at immediate post and follow-up program phases. Recommendations: Initiating in-service education and training programs in all departments for refreshing and increasing nurse managers' knowledge and skills especially about adaptive leadership.