Measuring individual differences in children's emerging language abilities is important to researchers and clinicians alike. The 2 most widely used methods for assessing children's vocabulary both have limitations: Experimenter-administered tests are time-consuming and expensive, and parent questionnaires have only been designed for children up to 37 months of age. Here, we test the validity of a new assessment to fill this gap: the Developmental Vocabulary Assessment for Parents (DVAP). In 4 experiments, we assess the reliability of this measure and its concurrent and predictive validity in samples of 2- to 7-year-old children. We found that the DVAP provides a rapid, cost-effective alternative to experimenter-administered vocabulary tests for children.