We propose and test a theoretical model focusing on antecedents and consequences of demographic faultlines. We also posit contingencies that affect overall team dynamics in the context of demographic faultlines, such as the study setting and performance measurement. Using meta-analysis structural equation modeling with a final data set consisting of 311 data points (i.e., k [predictor-criterion relationships]), from 39 studies that were obtained from 36 papers with a total sample size of 24,388 individuals in 4,366 teams, we found that sex and racial diversity increased demographic faultline strength more than did diversity on the attributes of functional background, educational background, age, and tenure. Demographic faultline strength was found to increase task and relationship conflict as well as decrease team cohesion. Furthermore, although demographic faultline strength decreased both team satisfaction and team performance, there was a stronger decrease in team performance than in team satisfaction. The strength of these relationships increased when the study was conducted in the lab rather than in the field. We describe the theoretical and practical implications of these findings for advancing the study of faultlines. (Contains 1 figure, 6 tables, and 4 footnotes.)