Diversity is "the collective amount of differences among members within a social unit" (Harrison & Sin, 2005, p. 196). In sport team contexts, the diversity of several member characteristics can have ramifications for group structure (e.g., roles), emergent states (e.g., cohesion), and processes (e.g., communication; Carron & Eys, 2012; McEwan & Beauchamp, 2014). One member attribute purported to be salient for groups is cultural background (Schinke et al., 2014). Although the effects of cultural diversity on group processes have been studied extensively in organizational psychology (e.g., Stahl et al., 2010), research in sport contexts is comparably rare. This study examined how member diversity (assessed via Blau's Index) of a typically overt aspect of culture, ethnicity (e.g., African-American, Asian, Indigenous, Hispanic), predicts team cohesion. Data were gathered from 203 intercollegiate athletes (87 males and 116 females) from 16 interdependent sport teams (e.g., basketball) at two time points (1-2 weeks apart). Controlling for cohesion at time 1, team size, average team tenure, and gender, team-level regression analyses revealed two task dimensions of cohesion at time 2 were positively predicted by in-group ethnic diversity at time 1: attractions to group-task, ? = 0.46, t(15) = 3.12, p =.011, ?R2 = 0.12, Overall model: Adjusted R2 = 0.81, F(1, 15) = 13.77, p<.001, and group integration-task, ? = 0.38, t(15) = 2.31, p =.043, ?R2 = 0.08, Overall model: Adjusted R2 = 0.78, F(1, 15) = 11.79, p=.001. Potential explanatory mechanisms of the current findings are discussed (e.g., coach promotion of team identity).