A barrier to meeting the goal of universal health coverage in India is the inequality in utilisation of health services between indigenous and non-indigenous people. This study aimed to explore the determinants of utilisation, or non-utilisation, of public healthcare services among the Santals, an indigenous community living in West Bengal, India. The study holistically explored the utilisation of public healthcare facilities using a framework that conceptualised service coverage to be dependent on a set of determinants – viz. the nature and severity of the ailment, availability, accessibility (geographical and financial), and acceptability of the healthcare options and decision-making around these further depends on background characteristics of the individual or their family/household. This cross-sectional study adopts ethnographic approach for detailed insight into the issue and interviewed 422 adult members of Santals living in both rural (Bankura) and urban (Howrah) areas of West Bengal for demographic, socio-economic characteristics and healthcare utilisation behaviour using pre-tested data collection schedule. The findings revealed that utilisation of the public healthcare facilities was low, especially in urban areas. Residence in urban areas, being female, having higher education, engaging in salaried occupation and having availability of private allopathic and homoeopathic doctors in the locality had higher odds of not utilising public healthcare services. Issues like misbehaviour from the health personnel, unavailability of medicine, poor quality of care, and high patient load were reported as the major reasons for non-utilisation of public health services. The finding highlights the importance of improving the availability and quality of care of healthcare services for marginalised populations because these communities live in geographically isolated places and have low affordability of private healthcare. The health programme needs to address these issues to improve the utilisation and reduce the inequality in healthcare utilisation, which would be beneficial for all segments of Indian population.