PurposeThis research discloses the effect of religiosity on purchasing intention through serial-mediation paths in a halal-certified food context. Borrowing from the identity theory while supplemented by the theory of planned behaviour (TPB) and the knowledge–attitude–practice (KAP) theory, a 4-layered framework is developed to investigate such an issue.Design/methodology/approach264 questionnaires are collected in the field study conducted in Tunis, Tunisia. Quota sampling method is applied. Testing of the hypotheses is performed using partial least square analysis.FindingsThe findings reveal that religiosity affects the four mediators—awareness, trust, subjective norm and perceived behavioural control—which in turn affect attitude, and purchase intention towards halal-certified food is eventually aroused. These four serial-mediation paths are further proved to form the mechanisms.Research limitations/implicationsThe field study participants are limited to consumers in Tunis. Besides, a mechanism to collect the data from general public including lower educated consumers should be necessary.Originality/valueThis research is a pioneering work investigating the sequential intervening effect in the religiosity-intention relationship in halal-certified food. The authors provide unique and fruitful insights into this relatively untapped field for academia and firms.