Back ground: Peri-conception care plays an essential and vital role for the health of the mother, her child and her family. Taking folic acid orally prior to conception and during the early stages of pregnancy plays a significant role in preventing Neural Tube Defects and has been associated with preventing other folic acid sensitive congenital anomalies. There exists problem in different parts of the globe on women's understanding of the importance of folic acid making them not to take this supplement in peri-conception period. Objective: This study aimed at assessing the knowledge of peri-conception folic acid supplementation among women visiting Maternal and Child Health clinics of public health facilities in Addis Ababa, Ethiopia. Methods: Institution based cross-sectional study was conducted from May 15 to June 20/2020 among 226 women visiting Maternal and Child Health clinics of health centers in Addis Ababa. Consecutive sampling technique was used to select study participants. Data were collected through interviewer administered structured questionnaire and analyzed using Statistical Package for Social Sciences version 24. Tables, charts and graphs were used for data presentation. Multivariable logistic regression analysis was done to identify the independent predictors of women's knowledge of folic acid at p-value ≤ 0.05. Results: More than two-third of the study participants, 156 (69.0%) had good knowledge on peri-conception folic acid supplementation and its health benefits. Participants with age 25-30 years were 2.14 times more likely to have good knowledge compared to those aged less than 25 years while women with age greater than 30 years were 5.20 times more likely to have good knowledge compared to those with age less than 25 years. Women who had attended high school were 2.93 times more likely to have good knowledge compared to those with no formal education. Likewise, women who had attended college and above were 4.18 times at odd of having good knowledge on periconception folic acid supplementation compared to those with no formal education. Women who had information on prenatal care were 1.48 times more likely to have good knowledge compared to those who never had no information. Conclusion: Folic acid supplementation knowledge in more than two third of the study participants was good. Participants' age, educational status and information on prenatal care were the independent predictors of knowledge on folic acid supplementation. The Ministry of health, Addis Ababa city health bureau, the study facilities' management as well as Non-Governmental Organizations working on health in the city should focus on means to increase knowledge of peri-conception folic acid health benefits for women with poor knowledge on the same.