<p>It is important to replicate the structure and properties of a scale in different populations, both related and distinct from the original study, in order to consolidate a measurement instrument and recommend its use, even in studies that do not utilize probability samples, which are common in psychology. The purpose of this article is to validate the Family and Friends Social Support Scale-Revised (AFA-R) among Mexican medical students. Its objectives include testing the structure of two correlated factors, assessing model invariance across sex, evaluating the internal validity, reliability, and discriminant validity of these two factors, describing the distribution of the scale and its factors; and testing its concurrent validity with self-esteem, life satisfaction, stress, and depression. A questionnaire composed of five scales—the AFA-R, Perceived Stress Scale, Zung Self-Rating Depression Scale, Satisfaction with Life Scale, and Rosenberg Self-Esteem Scale—was administered online to 600 medical students from three private medical universities in northeastern Mexico. Confirmatory factor analysis was employed. The two-factor model demonstrated a good fit to the data. The mean variance extracted was greater than 0.50, and the omega and H coefficients were above 0.90 for each factor. The heterotrait-monotrait ratio was less than 0.85, with a shared variance between the factors of 42.5%. The distributions exhibited positive skewness. The correlations with the four validity scales were significant, ranging from low to moderate. The structure and properties of the scale align with expectations and previous studies, thus recommending its use among medical students and its validation in other populations.</p>