Background: Continuing professional development is a lifelong process of active participation by nursing school's directors in learning activities that assist in developing and maintaining their continuing competence, enhancing professional practice and supporting teachers achievement. The study aimed: Was to assess the effect of educational program about continuous professional development for nursing school directors on their teacher achievement. Design: A quasiexperimental design. Setting: The study was conducted in all nursing schools at Kafr El-Shikh Governorate. Subjects: Consisted of two groups: First group nursing school directors (21) and second groups nursing school teachers (210). Tools: Four tools were used for data collection; (1) Continuous Professional Development Knowledge Questionnaire, (2) Continuous Professional Development Self-evaluation Report Questionnaire, (3) Continuous Professional Development Attitude Questionnaire (4) Nursing Teachers' Achievement Questionnaire. Results: Showed that low percent (19%, 23.8%, 19% respectively) of nursing school directors had adequate total level of knowledge, positive attitude, and high perception skill level regarding continuous professional development while, post- program this percent improved to majority (95.2%, 90.5%, 90.5%) of them had adequate level of knowledge positive attitude, and high perception skill level regarding continuous professional development respectively. pre-program low percent (27.1%) of nursing school teachers had good level of achievement. While, majority (87.2%) of them had good level of achievement post-program. Conclusions: A highly statistically significant positive correlation was found among nursing school directors and nursing school teachers (knowledge , perceptions, attitude & achievement) toward continuous professional development.at pre- and post-educational program. Recommendations: Top management in nursing schools at Kafr El-Shikh Governorate need to use continuing education programs as a strategy to raise nursing school directors regarding continuous professional development especially its principles and skills, and nursing school teachers' achievement.