Multireligious communities need to acquire multicultural competence (MC) to help them deal with complex interactions taking place in the repertoire of religious and cultural differences. Hence, this explanatory mixed-method study sought to quantitatively measure the MC of Indonesia’s multireligious communities and to qualitatively explore the factors contributing to the formation of their MC. A quantitative survey with 30-item valid and reliable questionnaires was conducted to measure the MC of 577 respondents from a population of Indonesia’s multireligious communities by using a convenient sampling technique. A descriptive qualitative study was further executed to explore the contributing factors of MC by involving 20 participants recruited using a purposive sampling technique. The data were analysed using descriptive-quantitative and interactive-model techniques. The quantitative data revealed that the multireligious communities had a high level of MC (M=3.64) demonstrated by high levels of multicultural awareness, skills, and knowledge with a balanced composition. The qualitative data highlighted five factors shaping their MC. These factors entailed mutual respect, tolerance, internalization of multicultural attitudes, good communication, and interactions with cultural traditions. Further studies could use these factors to develop multicultural education programs or interventions.