The millennial generation is the primary consumer group in Indonesia today, covering more than a quarter of the population. They are known for their familiarity with purchasing food products online. This research aims to understand purchasing behavior and the factors related to millennial consumers’ online food expenditure post-COVID-19 pandemic. Frequency analysis, ordinary least squares (OLS), and log-log regression were employed to explore purchasing behavior and factors pertaining to millennial consumers’ online food expenditure. A total of 182 millennial consumers from across Indonesia participated as respondents by filling out a self-administered questionnaire via Google Forms. The results disclosed that most respondents were late millennials with bachelor’s degrees who lived in urban areas and were within the middle-income group. Professionals dominated the occupation of the respondents, with monthly food expenditures below IDR 500,000. Their primary reason for purchasing food online was to save time, and they frequently did it 2-3 times per month, with fresh foods being the most commonly purchased item. Smartphones were the preferred device, and marketplaces were the most utilized platform. Regression analysis unveiled that higher purchase frequency and post-pandemic changes significantly raised online food expenditures among millennials.