Online food-safety educational programs are increasingly important to educate different populations as technology and culture shift to using more technology. However, the broad effectiveness of these programs has yet to be examined. A systematic review, random-effects meta-analysis, and thematic synthesis are conducted to identify the effect size of online food-safety educational programs on knowledge, attitudes, and practices of consumers, food workers, and students and their respective barriers and recommendations. Online food-safety education was found to be of moderate and low effectiveness, with attitudes being the lowest in all populations. Consumers struggled with staying focused, and it was found that messaging should focus on risk communication. Students struggled with social isolation and a lack of time, and it was recommended that videos be used. Food workers struggled with a lack of time for training and difficulty understanding the material, and future programs are recommended to implement shorter but more frequent trainings with simple language. Future online food-safety educational programs should focus on incorporating social elements, as they can remain a huge barrier to learning. They should also focus on changing the participant’s attitude to risk perception and beliefs in the importance of food safety.