Background: Sustainability in healthcare involves advancing the delivery of high-quality patient care for everyone by focusing on the three key aspects of sustainable development: environmental, social, and financial. Nurses are pivotal leaders in promoting environmental sustainability within this framework.. Aim: evaluate the effect of sustainable development educational program on nursing interns' students' knowledge, behaviors and attitudes. Design: A quasi experimental (one group pre-test/ post-test) design was utilized in this study. Setting: This study was conducted at the Faculty of Nursing, Cairo University /Egypt. Subjects: A systematic random sampling method used to recruit current sample (n=159) intern students who were enrolled in academic year 2022/2023. Tools: Two instruments were utilized: a personal characteristics data sheet and the Sustainability Consciousness Questionnaire (SCQ).Results: The findings indicated that the highest mean scores for the total knowledge, behavior, and attitude of nursing intern students were 80.9, 61.1, and 66.1, respectively, immediately following the program. During the follow-up after the educational intervention, these scores were 79.5, 58.14, and 65.3, respectively.. Conclusions: There was a highly statistically significant improvement in intern student' total and sub-dimensional knowledge, behavior, attitude regarding sustainable development after the educational intervention implementation as well as at the follow up phase. Thus, from these results the education intervention had success in achieving its objectives. Moreover, all hypotheses of the study are accepted.  Recommendations: Incorporating sustainability education into the existing nursing curriculum, offering hands-on, practical experiences for intern nursing students to implement sustainable practices in real healthcare settings, and conducting further nursing research to examine the relationship between sustainable management knowledge, behaviors, attitudes, and patient outcomes are crucial steps.