Empathy is an essential component of human social life. It requires the ability to understand another's mental state and respond with an appropriate emotion or action. Individuals with autism spectrum disorder (ASD) have been described to exhibit atypical empathic responses which limit communication and social interactions. This review highlights the clinical characteristics and mechanisms underlying empathy in ASD by summarizing 61 peer-reviewed articles. Studies characterized empathic differences due to sex, age, intelligence, and disorder severity and provided valuable insights into the roles that genetics, neural networks, and sensory processing have in eliciting empathy. This knowledge will lead to improved diagnostics and therapies to improve social cognition, emotional recognition, and the empathic response in patients with ASD.