This study explores the relationship between investor heterogeneity and firms’ post-seed funding performance. We find a statistically and economically significant negative association of investor heterogeneity on both a firm’ s likelihood of obtaining new funding and the amount raised in subsequent funding rounds. These findings suggest that greater heterogeneity among investors may impair board efficacy and weaken the quality of venture governance. Moreover, the marginal effect of investor heterogeneity is non-linear and diminishes over the course of a venture’ s funding lifecycle. Our results remain robust after accounting for endogeneity concerns and alternative measures of investor culture.