This study tests reciprocal influences of perceived homework quality, teacher autonomy support, homework effort, and achievement. Data from 702 8th graders over one school year showed positive reciprocal effects between (a) homework quality and autonomy support, and (b) effort and achievement. Higher prior effort and achievement led to higher homework quality. Autonomy support showed a more positive effect on later achievement when prior effort was high. Meanwhile, autonomy support showed a more positive effect on later effort and homework quality when prior effort was low. These findings hold important implications for teaching practice (i.e. autonomy support to compensate low effort).