The present study examined the negative effects of insufficient social support on mental-physical health of adolescents. Two types of insufficient social support were used; the gap between requested and received support and the gap between received and provided support. Five hundred and five adolescents responded to questionnaires that included items measuring received, requested and provided support, and adjustment and mental-physical health. Received support was classified into six factors by factor analysis. Results from multiple regressions indicated that (1) the higher requested-received support gaps were negatively associated with better adjustment and mental health. (2) There was little association between the received-provided support gaps and adjustment or mental health. (3) There was no association between each of the two gaps and physical health. And (4) the six factors of requested-received, the six factors of received-requested support gaps, and each factors of the two gaps, only accounted for extremely low variance in adjustment or mental-physical health.