Online interventions for anxious youth, like Cool Kids Online, improve access to care across Australia and are effective. Yet, current gold standards require frequent therapist support, limiting their cost-effectiveness and reach. Recent research in adult online interventions suggests that similar outcomes are possible with minimal or no therapist guidance. Therefore, this project will evaluate, for the first time, the efficacy of optional (on demand) and unguided child anxiety online programs using practices perfected in adult online intervention research. It will also explore whether there are certain factors that influence the amount of therapist contact families need for optimal outcomes.