Genotype-environment association (GEA) is widely used for identifying genetic variation linked to environmental pressures. Their proliferation over the past decade offers a critical opportunity to synthesize how adaptive variation is identified and distributed across broad taxonomic groups. Here, we reviewed 194 GEA studies from the Kingdom Animalia to summarize the analytical methods employed and the key predictors of adaptive variation. Our review revealed that latent factor mixed models (LFMM