This brief report presents preliminary psychometrics of responses to the Youth Externalizing Problems Screener (YEPS), which is a 10-item self-report rating scale intended for use as a screening instrument. The YEPS was designed to function as a companion measure to the Youth Internalizing Problems Screener (YIPS), facilitating the screening of broad mental health problems among students in secondary school settings. Analyses presented herein were conducted with the same small, preliminary samples of urban high-school students as those reported on for the initial development and validation of the YIPS (Sample 1: n = 177, Sample 2: n = 219). Results suggest that responses to the YEPS showed a sound, unidimensional factor structure that is internally consistent, providing initial evidence for the purported internal structure of the measure. Findings also showed that YEPS scores had meaningful associations with other self-reported, theoretically relevant mental health variables, providing initial convergent evidence in favor of construct interpretation. Taken together, preliminary psychometrics support the validation argument for the interpretation and use of YEPS scores as a brief measure of adolescents' general externalizing problems. Implications for future research and practice are discussed.