Evidence on the association of religiosity and academic attainment is consistent, thus suggesting additional factors intervene in this relationship. We proposed and tested a model with two concepts from the field of positive psychology: psychological capital and psychological resilience. We hypothesised that these mediate the association between religiosity, demographic variables and academic achievement. We tested the model in a sample of 119 senior students in a Catholic university in Poland. The results partially supported the model; both psychological capital and psychological resilience mediated the association between religiosity and academic attainment but in different directions. Among the demographic variables, only age associated directly with achievement. The results are discussed in light of the existing evidence and positive psychology theory.