Prior studies showed that general basic psychological need satisfaction or social support affected academic engagement. However, it remains unknown how the mutual reinforcement between the perception of internal needs and external support influences adolescents' academic engagement, as well as whether academic engagement can shape psychological resources and a positive environment. This study aims to examine the bidirectional longitudinal relations between general basic psychological need satisfaction, social support, and academic engagement among Chinese adolescents. A total of 1,214 high school students (M[[subscript age] = 15.46 years, SD[subscript age] = 0.71) completed questionnaires at three time points with a six-month interval. Results revealed bidirectional relations between general basic psychological need satisfaction and social support with academic engagement, as well as between general basic psychological need satisfaction and social support themselves. Additionally, general basic psychological need satisfaction and social support mutually reinforced each other, indirectly predicting academic engagement; academic engagement predicted general basic psychological need satisfaction through social support and mediated the relation between social support and general basic psychological need satisfaction. This study revealed that the perception of internal needs and external support mutually promoted academic engagement which also shaped the perception of internal needs and external support. It is important to shape these two resources while considering the role of academic engagement in developing resources.