In this article, we use data from a large-scale Brazilian national assessment to discuss the relation between reform teaching and equity in mathematics education. We study the dimensionality of teaching style to better qualify what reform teaching means. We then use hierarchical linear models to explore whether reform teaching is associated with student achievement in mathematics and with student socioeconomic status (SES). Our results indicate that reform and traditional teaching are not opposite sides of a one-dimensional axis. They also emphasize both that reform teaching is related to higher school average achievement in mathematics and that the dissemination of reform teaching contributes to minimize the achievement gap between students who attend schools with low average SES and students who attend schools with high average SES. However, our results also show that reform is associated with an increase in within-school inequality in the social distribution of achievement.