To assess the knowledge, attitudes, and practices of adults regarding the implementation of calorie labeling in restaurants in Riyadh, Saudi Arabia. Methods: This was a cross-sectional study of 1443 adults invited to complete a self-administered questionnaire consisting of 4 parts that assess demographics, knowledge, attitudes, and practices of mandatory menu labeling. The survey was conducted in all 5 regions of Riyadh. Results: We entered 1265 surveys into final data analysis with a response rate of 88%. Of this, 1036 participants (82%) understood the meaning and values of calories, while 53% knew the average daily caloric intake. Regarding participants' attitudes, 1053 (83%) perceived the importance of calorie labeling and (88%) supported this policy. Approximately 50% (n=626) Original Article of the participants were significantly more likely to be influenced by the calorie labeling to place a healthier order. Married (p=0.050), educated (p<0.001), and higher monthly income (p<0.001) were significantly influenced to place a healthier restaurant order compared to their peers. Conclusion: Adults in Riyadh showed satisfactory knowledge, attitude, and practice since the implementation of this policy. Our findings showed that knowing the value of calories and average caloric intake had a significant positive influence for a healthier diet. This highlights the importance of menu labeling regulations campaigns for the public.