Anthropomorphism—the attribution of human qualities to non-human objects—is believed to be a natural tendency which may serve several adaptive functions. One possibility is that anthropomorphism provides an egocentric heuristic by which we can understand the world. It may also be a strategy for reducing our subjective sense of loneliness. However, not all humans exhibit the same propensity to anthropomorphise. Recent findings suggest that autistic individuals may be more likely to anthropomorphise than non-autistic individuals. In Study 1, we conducted a large-scale survey of autistic traits and dispositional anthropomorphism in the general population (n = 870). We found that individuals who reported having more autistic traits had an increased dispositional tendency to anthropomorphise non-human entities. In Study 2, we more closely examined variation in anthropomorphism tendencies in a sample of autistic adults (n = 90) to better understand what might drive increased anthropomorphism in this population. We found that those with greater anthropomorphism tendencies experienced greater levels of self-reported loneliness. We propose that increased anthropomorphism might reflect reduced opportunities for social connection for autistic people and those with more autistic traits.