Cross-cultural studies are regarded as quasi-experimental research, and threats that jeopardize the validity of cross-cultural differences and their explanations are reviewed. The consilience approach is advocated for strengthening cross-cultural invariance, which calls for diverse evidence based on a sound theoretical basis, multiple sources of data, different research methods, and explicit refutation of alternative interpretations. Three broad strategies for strengthening cross-cultural invariance are proposed under the consilience framework, including the systematic contrast of cultural groups, the inclusion of covariates to rule out alternative explanations, and the use of multiple research methods.