This Evidence Base Update of parent-report measures of youth anxiety symptoms is a companion piece to our update on youth self-report anxiety symptom measures (Etkin et al., 2021). We rate the psychometric properties of the parent-report measures as Adequate, Good, or Excellent using criteria developed by Hunsley and Mash (2008) and Youngstrom et al. (2017). Our review reveals that the evidence base for parent-report measures is considerably less developed compared with the evidence base for youth self-report measures. Nevertheless, several measures, the parent-report Screen for Child Anxiety-Related Emotional Disorders, Multidimensional Anxiety Scale for Children, and Spence Children's Anxiety Scale, were found to have Good to Excellent psychometric properties. We conclude our review with suggestions about which parent-report youth anxiety measures are best suited to perform different assessment functions and directions for additional research to expand and strengthen the evidence base.