Combining organizational learning theory and institutional theory, this study examines how managerial learning affects the new product innovativeness of high-tech firms in an emerging market and assesses whether such an effect is conditional on institutional support. Based on a survey of 174 high-tech firms in China, the study finds that managerial learning helps firms increase the innovativeness of their new product but that such an effect declines at high levels of managerial learning. Furthermore, institutional support at the government level enhances the effect of managerial learning on new product innovativeness; while organization-level institutional support reduces the effect of managerial learning on new product innovativeness. This study sheds further light on the driving forces of new product innovativeness for firms in an underdeveloped institutional environment.