Previous research suggests that empathy is a strong contributor to altruistic behavior. However, there is a lack of research regarding the role of empathy in long-term, effortful altruistic acts such as volunteering. In this preregistered study, we aimed to understand the moderating role of belief in a just world in the association between induced empathy and intentions to volunteer among both volunteers (N = 99) and non-volunteers (N = 203). Participants were randomly assigned to either the experimental group (N = 149) or the neutral group (N = 153). In the experimental group, participants read a text about the suffering of an individual with a chronic illness. In the control group, participants read a text about a typical Tuesday for someone. Then, all participants were asked to complete surveys regarding empathy levels, prosocial intentions, belief in a just world, and demographics. Results showed that inducing empathy did not directly affect the levels of intention to volunteer in the future. However, empathy induction was effective for non-volunteers, particularly those with lower levels of personal (but not general) belief in a just world. These results suggest that increasing levels of empathy might be ineffective when personal belief in a just world poses a barrier to displaying volunteering acts. Notably, these findings were observed specifically for non-volunteers, not for volunteers. Thus, future research should explore potential differences due to previous volunteering experiences and the levels of belief in a just world in the motivating roles of empathic concerns for displaying long-term, effortful helping behaviors.