The ideological psychological contract (PC) describes perceived obligations related to an organization’s mission, values, and principles. The lack of research regarding ideological PC breach and fulfilment is surprising, as theory states that this PC type has distinct effects on outcomes. We address this gap in the literature and investigate how ideological PC breach and fulfilment influence volunteers’ work effort and whether this effect differs from relational PC breach and fulfilment. We measured promised and delivered ideological and relational inducements on two separate occasions and used polynomial regressions and response surface analyses to test our hypotheses. In the case of ideological PC fulfilment, results indicated that work effort increases in situations of mutual-low and mutual-high obligations. In the case of ideological PC breach, work effort increases in situations of under- and overfulfilment. We conclude that underfulfilment of ideological PCs differed from relational PCs, as work effort decreases in the case of the latter. Hence, our findings demonstrate the importance of considering the unique nature of ideological obligations in the PC literature.