Hundreds of articles have explored the extent to which individuals accept evolution, and the Measure of Acceptance of the Theory of Evolution (MATE) is the most often used survey. However, research indicates the MATE has limitations, and it has not been updated since its creation more than 20 years ago. In this study, we revised the MATE using information from cognitive interviews with 62 students that revealed response process errors with the original instrument. We found that students answered items on the MATE based on constructs other than their acceptance of evolution, which led to answer choices that did not fully align with their actual acceptance. Students answered items based on their understanding of evolution and the nature of science and different definitions of evolution. We revised items on the MATE, conducted 29 cognitive interviews on the revised version, and administered it to 2881 students in 22 classes. We provide response process validity evidence for the new measure through cognitive interviews with students, structural validity through a Rasch dimensionality analysis, and concurrent validity evidence through correlations with other measures of evolution acceptance. Researchers can now measure student evolution acceptance using this new version of the survey, which we have called the MATE 2.0.