Parental negative beliefs about child anxiety (PBA; e.g., thoughts that experiencing anxiety is harmful for the child) are significantly associated with child anxiety, parental involvement in child anxiety treatment, and parental accommodation of anxious child behaviors, suggesting that parents high in PBA might engage in overprotective and restrictive parenting behaviors. The parental behaviors of overcontrol (OC) and autonomy granting (AG) are also linked to child anxiety; however, the mediating role of PBA in the context of parental and adolescent anxiety and parental OC and AG has not been examined. Online survey self-report data were collected from 119 adolescents and their parents (54 mother-adolescent dyads and 57 father-adolescent dyads), on the variables of adolescent anxiety, parent- and adolescent-reported AG and OC, and PBA to test exploratory models of these constructs. PBA correlated significantly with adolescent anxiety and adolescent- and parent-reported OC, but with neither adolescent- nor parent-reported AG. PBA partially mediated the relationship between parental anxiety and OC in the full sample and for fathers, but not mothers. PBA also significantly mediated the relationship between parent- and adolescent-reported OC and adolescent anxiety, both in the full sample as well as for the father and mother subsamples. For mother dyads, parental anxiety was correlated with OC, but not AG, whereas for father dyads, paternal anxiety was associated with AG, but not OC. Findings suggest that addressing parents’ beliefs about their adolescent’s anxiety might provide one potential point of intervention when attempting to address overprotective behaviors that might impede an adolescent’s treatment outcome.