Laypersons' belief in free will may foster a sense of thoughtful reflection and willingness to exert energy, thereby promoting helpfulness and reducing aggression, and so disbelief in free will may make behavior more reliant on selfish, automatic impulses and therefore less socially desirable. Three studies tested the hypothesis that disbelief in free will would be linked with decreased helping and increased aggression. In Experiment 1, induced disbelief in free will reduced willingness to help others. Experiment 2 showed that chronic disbelief in free will was associated with reduced helping behavior. In Experiment 3, participants induced disbelief in free will caused participants to act more aggressively than others. Although the findings do not speak to the existence of free will, the current results suggest that disbelief in free will reduces helping and increases aggression.