Indonesia is one of the world’s biggest halal food product and service consumers. The halal industry will continue to expand as the Muslim community’s needs grow. Therefore, application development for online halal food providers through the Go Food and Shopee Food platforms is in high demand. This paper aims to analyze the determinants of Go Food and Shopee Food users’ halal food purchase decisions. The theory of planned behavior (TPB), the theory of consumer behavior, and the unified theory of acceptance and utilization of technology (UTAUT2) were used. The research sample consists of Go Food and Shopee Food users chosen randomly from a pool of 104 respondents. The data were collected using a questionnaire developed from previous studies and the theories applied (TPB and UTAUT2). Respondents received questionnaires online via Google Forms. Path analysis was used in this study. The findings show that TPB constructs can adequately explain halal food purchase behavior. The attitude toward the purchase of halal food and subjective norms affect the user’s intentions to purchase halal food. The coefficients are 0.291 and 0.379, with a p-value < 0.001. The user’s intention determines the positive decision to purchase halal food with a coefficient of 0.843 and a p-value < 0.001. Halal awareness is a powerful predictor with a coefficient of 0.206 and a p-value of 0.014. However, perceived behavioral control, halal literacy, religious commitment, financial literacy, and UTAUT2 constructs (price value, hedonic motivation, and habit) were not found to determine the intention to purchase halal food.