This study aims to determine restaurant patrons’ perceptions of functional foods. A questionnaire was employed as the data collection method. While the population of the study consisted of restaurant consumers in Türkiye, restaurant patrons in Istanbul were selected as the sample due to time and financial constraints. Data were collected from 404 participants through convenience sampling. The Functional Food Perception Scale developed by Landström et al. (2007) was used in the study. Data were analysed using SPSS 22 software, and normality analysis, exploratory factor analysis, confirmatory factor analysis, reliability analysis, t-tests, ANOVA, correlation, and regression analyses were conducted. The findings revealed that restaurant patrons generally hold positive perceptions of functional foods. Participants’ levels of functional food awareness, nutritional knowledge, healthy eating intention, perceived benefits, and health perception were found to be above the average level. In addition, more than half of the participants reported consuming functional foods at least a few times a week. Statistically significant and positive relationships were identified among the sub-dimensions of the scale. In particular, a strong relationship was found between healthy eating intention and perception of functional foods. However, demographic variables such as gender, marital status, age, education level, and income did not create significant differences in functional food perceptions. The findings are expected to contribute to functional food producers, restaurant businesses, and researchers in the field of gastronomy by providing a better understanding of consumer behaviour toward functional foods.