The present study used a person-centered approach to identify math motivation profiles under self-determination theory, and examine whether math achievement varies across different profiles. Data were collected from 2,137 children. Five student motivation profiles were identified: a “high quality” profile characterized by high levels of intrinsic and identified motivation and a low level of controlled motivation, a “high quantity” profile characterized by high levels of these three kinds of motivation, a “low quantity” profile characterized by low levels of these three kinds of motivation, a “poor quality” profile characterized by a high level of controlled motivation and low levels of intrinsic and identified motivation, and a “low autonomous motivation” profile characterized by very low levels of intrinsic and identified motivation. These five profiles differed in math achievement. We found that students in the high quality profile had the highest level of math achievement compared to those in the other profiles. This result indicated that the quality of motivation was more important than the amount of motivation.