Background: Separate lines of research have shown that higher levels of parental overcontrol and parental anxiety are related to higher levels of child anxiety. The mechanisms of transmission, however, are poorly understood. Objective: It has been theorized, though not empirically tested, that parental overcontrol and anxiety increase children's interpretation bias by signaling to the child that the environment is threatening (e.g. through modeling or restriction of autonomy), thus increasing the child's anxiety level. Methods: The present study investigated this theory using 75 parent-child dyads (parents aged 27-52, 82% female; children aged 7-12, 52% female, 80% Caucasian). All parents were diagnosed with a primary anxiety disorder, while no child was diagnosed with an anxiety disorder. Results: Children's interpretation bias, measured using ambiguous stories, was shown to partially mediate the relation between parental overcontrol and child anxiety and completely mediate the relation between parental anxiety and child anxiety. There was no significant relation between parental overcontrol and parental anxiety. Conclusions: Findings partially support theoretical models, which posit that higher levels of overcontrol and parental anxiety signal to children that their environment is threatening, perhaps increasing their threat appraisal of ambiguous situations and increasing their anxiety. Implications and directions for future research are discussed.