Previous studies have shown that willingness to help particular victims is predicted separately, or in combination, by the belief in a just world (BJW) and self-efficacy to promote justice in the world (SEJW). Our goal was to extend this knowledge by studying general attitudes towards helping and the association between BJW and SEJW in people that do volunteer service, and by comparing the predictive power of two spheres of BJW, personal BJW and general BJW, on helping attitudes. We measured personal BJW, general BJW, SEJW and helping attitudes in two samples (one comprising university students and the other only volunteers). The results differed in the two samples. For volunteers endorsing strong self-efficacy to promote justice in the world, personal BJW was associated positively with helping attitudes (p = .007). For participants endorsing weak self-efficacy to promote justice in the world, personal BJW was not associated with helping attitudes in either sample. General BJW was not associated with helping attitudes in either sample, either independently or in interaction with self-efficacy to promote justice in the world. The theoretical and practical implications of these results are discussed.