Scholars have not adequately assessed how organizational cultures in schools differentially influence students' mathematics achievement by race and socioeconomic status (SES). We focus on what we term "collective pedagogical teacher culture", highlighting the role of professional communities and teacher collaboration in influencing mathematics achievement. Using cross-classified growth models, we analyze data from the Early Childhood Longitudinal Study and illustrate that schools where teachers perceive the presence of professional communities and teacher collaboration foster greater mathematics achievement throughout elementary school. Furthermore, achievement gaps by race and socioeconomic status are lessened in schools with professional communities and teacher collaboration. (Contains 2 tables, 6 figures and 9 notes.)