This study investigated social support networks (father, mother, classmates, and teachers) in a sample of 447 adolescents aged between 12 and 18 years. Using a cross-sectional design, the main aim was to analyze differences in the sources of family and school support during adolescence based on a multidimensional perspective, focusing on the frequency of and satisfaction with emotional, instrumental, and informational support provided by the sources. The results suggest that the mother is the main provider of support. Parents mainly provide emotional and instrumental support, classmates provide informational and emotional support, and teachers provide informational support. Informational support was provided significantly more frequently than any other type and satisfaction with informational support was greater. There was a trend for parental support to decrease as support from classmates increased. We also found gender differences; compared with boys, girls received less support from the father and more support from classmates.