<p>When making prosocial decisions, people usually experience more than one dimension of distance simultaneously. However, little research has explored the joint influence of social distance and spatial distance on altruistic behavior. The present research investigated the moderating effect of spatial distance on the relationship between social distance and altruistic behavior and examined whether this moderation could be observed only for individuals with proself orientation rather than those with prosocial orientation. In Study 1, 98 undergraduate students completed scenario-based tasks designed to manipulate spatial distance and social distance, and reported their willingness to help. The results demonstrated that the beneficial effect of close (vs. distant) social distance on altruistic behavior was stronger when spatial distance was near rather than distant. Building on the person-environment interaction model, Study 2 further explored the potential boundary condition of this moderation, i.e., social value orientation. After completing the measurement of social value orientation, 77 undergraduate students were selected and completed the dictator game in the same social scenario as Study 1. The results indicated that the moderation effect of spatial distance was only observed for individuals with proself orientation but did not hold for individuals with prosocial orientation. Taken together, these findings highlight the importance of considering personality traits to understand the joint influence of social and spatial distance on altruistic behavior.</p>