The current study examined the influence of multiple factors on individual differences in empathy; namely, attachment, negative emotionality, and emotion regulation. A total of 63 mothers completed the Attachment Q-set and questionnaires about their children's empathy, negative emotionality, and emotion regulation when children were 3 years old. Prosocial behavior was observed during a baby-cry procedure. Results of path analyses indicated that a model with attachment predicting empathy through the mediation of emotion regulation was the best fit for the data. Specifically, more-secure children were rated higher in emotion regulation and, consequently, higher in empathy. Furthermore, the optimal model was used to test empathy as a predictor of observed prosocial behavior. Here, children higher in empathy were observed to behave more prosocially. Overall, the results support the notion that more-secure children are more empathic because they are better emotion regulators.