The purpose of this study was to investigate the associations between beliefs about filial piety, implicit theories of romantic relationships, and relational intimacy in romantic relationships among Chinese youth. We surveyed 205 youths in Taiwan who were in romantic relationships to learn their beliefs about filial piety, implicit beliefs about romantic relationships, and relational intimacy. The results of our structural equation modeling showed that beliefs about reciprocal filial piety are positively associated with relational intimacy and beliefs about the growth of romantic relationships are negatively associated with beliefs about destiny. In addition, authoritarian parenting can lessen relational intimacy by instilling stronger beliefs about destiny in romantic relationships. However, beliefs about growth in romantic relationships are not associated with relational intimacy.