ABSTRACT This study investigates the complex interplay between language policies, religious beliefs, and cultural identity within two Indonesian Muslim families, residing in urban and rural contexts. Given Indonesia’s diverse linguistic landscape, with over 700 languages spoken, this research examines how religious beliefs and cultural identity shape their language ideology and their utilisation of the Indonesian language, local languages, and Arabic within Indonesian Muslim families. This research fills a gap, as there is limited literature on this topic in Indonesia. Through a case study design, including semi-structured interviews with two families in different contexts, the study explores language use for daily communication, cultural preservation, and religious practices. Findings reveal that the urban family members prioritise the Indonesian language for broader communication, while the rural family members maintain stronger ties to local languages to preserve their cultural identity. Their religious convictions place Arabic as a language designated for religious purposes rather than for daily communication. The study underscores the significance of religious beliefs in shaping language choices and highlights the challenges and strategies to preserve cultural identity and religious devotion. This research contributes to the understanding of how faith and cultural identity influence language ideology and practices in Indonesia’s multilingual society.