The Early Childhood Environment Rating Scale–Revised (ECERS–R) is widely used to associate child care quality with child development, but its validity for this purpose is not well established. We examined the validity of the ECERS–R using the multidimensional Rasch partial credit model (PCM), factor analyses, and regression analyses with data from the Early Childhood Longitudinal Study Birth Cohort. The PCM identified rating category disordering, indicating previously unrecognized problems with the scale's response process validity. Factor analyses identified neither a single factor nor the ECERS–R six subscales, replicating prior research regarding the scale's structural validity. Criterion validity results were mixed, with small effect sizes for regressions predicting child outcomes and moderate effect sizes for regressions predicting teacher-reported quality. Our results lend empirical support to recent critiques of the ECERS–R, and we discuss implications for its future use and for the development of future measures.