Prosocial behavior is altruistic conduct devoted to benefitting others, benefitting one’s community, and reinforcing conventional behaviors that serve a public good. The aim of the present study is to examine the psychometric properties of the Prosocial Behavior Scale (PBS) among male and female Portuguese youth participants (N = 559 youth, M = 16.51 years, SD = 1.07, range = 14–20 years). A two-factor intercorrelated model obtained the best fits, and the fits of a second-order model were also acceptable. Internal consistency as measured by the alpha and omega reliability estimators was good. Significant associations were found with psychometric measures of relevant constructs (e.g. self-control, psychopathic traits, criminogenic cognitions), and external criterion-related variables (e.g. engaging in illegal activities, alcohol and drug abuse). Cross-gender measurement invariance was established, with females scoring significantly higher than males on the PBS and its factors. Our findings support the use of the PBS as a valid and reliable measure of prosociality.