BACKGROUND: Persons with serious mental illness (SMI) continue to be largely taken care of by their families in India. Religion-based explanatory models of illness and religious coping methods are commonly employed by caregivers to deal with the burden of caregiving. While there is evidence to support the positive impact of religiosity on caregiving, there are no qualitative studies that have explored these beliefs. OBJECTIVE: This study aims to examine the experience of religiosity and coping among primary caregivers of persons with SMI. STUDY DESIGN: This study applied a qualitative study design using interpretative phenomenological analysis through face-to-face interviews. SETTING: The study was conducted between June 2022 and October 2023 at the Occupational Therapy Unit of the Department of Psychiatry at a tertiary care centre in South India. PARTICIPANTS: 24 primary caregivers of persons with SMI who provided written informed consent participated in the study. RESULTS: All participants had religion-based explanations for their relatives' mental illness. These explanations influenced perceptions about the role of healthcare professionals and the need to seek medical treatment for mental illness. Many participants simultaneously believed in medical, religious and social models of mental illness. Religious models of mental illness often led to fears of stigma, preventing participants from seeking support or healthcare services. CONCLUSION: The findings of our study demonstrate how religious beliefs of caregivers influence attributions to the cause and mode of treatment of mental illness. In order to optimise care for persons with mental illness, healthcare professionals need to involve themselves in dialogues regarding religious beliefs, formulate psychoeducation and care plans which incorporate these beliefs.