We hypothesized that people's personal belief in a just world (PBJW) is associated with decreased relationship-based dishonesty. We tested our hypothesis in 11 studies using community samples and different methodological approaches. One internal meta-analysis across all 11 studies (total N = 4970) yielded a negative but non-significant overall effect (Fisher's z = −0.07), thus providing no support for our hypothesis. A more detailed look revealed that studies measuring estimated levels of partner's dishonesty yielded significantly stronger negative associations to people's PBJW compared to studies that measured dishonesty emanated by oneself. We discuss what the results mean for research on belief in a just world and derive new approaches for future research in this field.