BACKGROUND: Socioeconomic status (SES) is a critical multifactorial determinant of health and plays a significant role in shaping an individual's health outcomes. While a composite scale has been proposed to measure SES in children, to our knowledge, limited composite scales were developed for adults in different contexts, highlighting the need for a comprehensive and valid SES measure to elucidate the relationship between SES and health in this population. OBJECTIVE: This study aimed to develop and validate a composite scale that measures the socioeconomic status in Lebanon and assess its correlates in a socioeconomic crisis context. METHODS: An online study was carried out between October and November 2022 across all Lebanese regions. Snowball sampling was used to enroll 448 adults living in Lebanon through a questionnaire created on Google Forms and shared by WhatsApp to a first sample from all geographic areas. RESULTS: The developed composite scale (SES-C) was found to be reliable and valid. It was based on several aspects of socioeconomic status, i.e., participant education level, family head education level, perceived social class, not being in debt, not receiving financial help, crowding index, participant work status, family head work status, monthly household income, and financial well-being. Furthermore, high SES was significantly associated with married status, older age, alcohol consumption, the absence of chronic disease, easy access to healthcare, private insurance coverage, and the number of rooms in the house in the bivariate analysis. In the multivariable analysis, high SES was significantly associated with age (ORa-1.13; p = 0.011) and easy access to healthcare (ORa = 7.81; p = 0.001) and inversely associated with chronic disease (ORa = 0.17; p = 0.002). Similar results with lower magnitude were found for moderate SES. CONCLUSION: The study successfully developed and validated a composite scale (SES-C) for measuring the socioeconomic status in Lebanon, taking into account the complexities of the Lebanese context. The scale was found to be reliable and valid, and its results showed significant correlations with various factors such as older age, lower risk of chronic disease, and easy access to healthcare.