This study aims to examine the psychometric properties of the Medical Outcomes Study-Social Support Survey (MOS-SSS-A) in a sample of adolescents in Puerto Rico. The sample consisted of secondary data of 787 students, ranging in age from 10 to 18, who attended public schools located in the southeast and northeast of Puerto Rico. We conducted a confirmatory factor analysis to test the factorial structure of the MOS-SSS-A. Additionally, correlations among perceived social support, depression, and anxiety were evaluated as evidence of discriminant validity. Results indicated a better fit when using the four-factor original model. Perceived social support scores were negatively correlated with depression and anxiety scores, which evidence discriminant validity. In conclusion, the MOS-SSS modified for adolescents (MOS-SSS-A) could be a valuable instrument for evaluating its role in reducing or preventing psychopathologies and offering early interventions for high-risk populations such as adolescents from minority groups.