Virtual Reality (VR) has been touted as an effective empathy intervention, with its most ardent supporters claiming it is "the ultimate empathy machine." We aimed to determine whether VR deserves this reputation, using a random-effects meta-analysis of all known studies that examined the effect of virtual reality experiences on users' empathy (k = 43 studies, with 5,644 participants). The results indicated that many different kinds of VR experiences can increase empathy, however, there are important boundary conditions to this effect. Subgroup analyses revealed that VR improved emotional empathy, but not cognitive empathy. In other words, VR can arouse compassionate feelings but does not appear to encourage users to imagine other peoples' perspectives. Further subgroup analyses revealed that VR was no more effective at increasing empathy than less technologically advanced empathy interventions such as reading about others and imagining their experiences. Finally, more immersive and interactive VR experiences were no more effective at arousing empathy than less expensive VR experiences such as cardboard headsets. Our results converge with existing research suggesting that different mechanisms underlie cognitive versus emotional empathy. It appears that emotional empathy can be aroused automatically when witnessing evocative stimuli in VR, but cognitive empathy may require more effortful engagement, such as using one's own imagination to construct others' experiences. Our results have important practical implications for nonprofits, policymakers, and practitioners who are considering using VR for prosocial purposes. In addition, we recommend that VR designers develop experiences that challenge people to engage in empathic effort.