There is empirical evidence to suggest that oral language and vocabulary on entering kindergarten are the best predictors of later reading success. Identifying skills that are predictive of later achievement using psychometrically sound measurement methods is a necessary component of early intervention efforts. Currently, there are limited methods for measuring early vocabulary acquisition. The Dynamic Indicators of Vocabulary Skills (DIVS) were designed to measure the vocabulary of preschool and kindergarten students. The purpose of this article is to contribute to the psychometric evidence supporting the use of the DIVS as effective measures of early vocabulary acquisition. This article presents an array of validity evidence for the DIVS, including predictive validity and the construct validity evaluated by both convergent validity and discriminant validity estimates.