Background: Prevention of vitamin D deficiency is a public health priority, as it has severe and long lasting consequences on general health of children and women. Aim: To evaluate the effect of educational program on women knowledge regarding vitamin D deficiency. Subjects and Methods: Quasi-experimental (Pre-post-test) research design was applied on 300 women in Maternal and Child Health centers. Tool: Part (1): Personal data, Part 2 and 3: Women's knowledge regarding vitamin D deficiency among women and children. Results: the present study showed that 47.3%, 44.3% and 39.7% of women gave incorrect answer about the sources of vitamin D, the benefits and its role for women and vitamin D benefits for children in pretest respectively; which improved in posttest p-values= 0.001. There were statistical significance differences between women knowledge regarding vitamin D with their age, educational level and marital status in pretest while there weren't in post program. Conclusion: Existence of inadequate level of knowledge regarding vitamin D deficiency, maternal knowledge was significantly affected by age, educational level, marital status and religion. The educational program improved knowledge regarding vitamin D among women. Recommendations: Educational campaigns and health promotion programs targeted women to increase knowledge about adequate intake of vitamin D..