BackgroundKnowing what to eat and realizing the significance of healthful eating habits are among the important steps to promoting eating behavior. The current study aims to assess the nutrition knowledge (NK) among a convenient sample in four different countries, determine the association between different demographic factors and NK, and investigate the need for future interventions on nutrition in the four selected countries.MethodsA cross-sectional multi-national survey study among a convenient sample of 8,191 subjects from Egypt, Syria, Saudi Arabia, and Jordan who undertook surveys between January 2019 and January 2020. A pre-tested interview questionnaire was utilized for data collection from study participants. It included three sections: i) Sociodemographic characteristics:. ii). Section two included twenty-one questions related to NK.. iii). Section three included one question about NK sources.ResultsAbout three-quarters showed inadequate nutrition knowledge (73.1%). Youth (15–24 yrs.) were more dependent on social media, with 87% using it as a primary source of NK, while adults (≥ 25 yrs.) demonstrated that 43% of them used social media. In contrast, TV was more prominent among them, with participants’ characteristics such as living with parents, body mass index, and country of residence showing no association with NK. However, female sex, education, and reading nutrition articles are significantly correlated with adequate knowledge (p< 0.001). Significant predictors of satisfactory knowledge were age, sex, education, living with parents, and reading nutrition articles.ConclusionThe study revealed low levels of NK indicating an urgent need to implement educational programs to promote nutrition knowledge. As NK is a modifiable determinant of diet intake and can positively impact the need for developing strategies in counselling and raising awareness among the general population to improve their health status.