Worry is a central component to anxiety, and intolerance of uncertainty (IU) is an identified factor contributing to worry. It has been noted that parenting behaviors play a role in the anxious development of youth, specifically with regard to these constructs. We sought to examine the relationship of parenting behaviors in the development of IU. Internet-based assessments of current anxiety, worry, and depression were correlated with retrospective reports of parental behavior. It was found that IU was significantly correlated with worry, anxiety, and depression. Additionally, in several mediation analyses, it was noted that IU was a mediator between perceived anxious rearing and both worry and anxiety, but not depression. The implications of these results and internet-based methodology are discussed, particularly in terms of the novel findings from IU mediation analyses.