Informed by theoretical frameworks and related literature concerning intrinsic motivation, favorability, motivational interference, and time management, the current study uses cross-lagged panel models to investigate the longitudinal relations among homework intrinsic motivation, favorability, time management, and math achievement, using data from 1450 Chinese 8th graders over two time points. Results indicated there were positive reciprocal influences of intrinsic motivation and favorability; higher prior intrinsic motivation led to higher subsequent favorability, and higher prior favorability led to higher subsequent intrinsic motivation. Additionally, higher prior time management resulted in higher subsequent intrinsic motivation, favorability, and math achievement. Finally, our study suggests that measuring favorability could be a complementary approach to investigate motivational conflicts in the field of motivational interference.