Using data from 217 research reports (N = 36,071, compared to 3,471 and 5,433 in previous meta-analyses), this meta-analysis investigated the conceptual and methodological conditions under which Implicit Association Tests (IATs) measuring attitudes, stereotypes, and identity correlate with criterion measures of intergroup behavior. We found significant implicit-criterion correlations (ICCs) and explicit-criterion correlations (ECCs), with unique contributions of implicit (β = .14) and explicit measures (β = .11) revealed by structural equation modeling. ICCs were found to be highly heterogeneous, making moderator analyses necessary. Basic study features or conceptual variables did not account for any heterogeneity: Unlike explicit measures, implicit measures predicted for all target groups and types of behavior, and implicit, but not explicit, measures were equally associated with behaviors varying in controllability and conscious awareness. However, ICCs differed greatly by methodological features: Studies with a declared focus on ICCs, standard IATs rather than variants, high-polarity attributes, behaviors measured in a relative (two categories present) rather than absolute manner (single category present), and high implicit-criterion correspondence (k = 13) produced a mean ICC of r = .37. Studies scoring low on these variables (k = 6) produced an ICC of r = .02. Examination of methodological properties-a novelty of this meta-analysis-revealed that most studies were vastly underpowered and analytic strategies regularly ignored measurement error. Recommendations, along with online applications for calculating statistical power and internal consistency are provided to improve future studies on the implicit-criterion relationship. (PsycINFO Database Record (c) 2019 APA, all rights reserved).