Anxiety is one of the most common mental health problems in childhood, and causes severe and persistent impairment in children's lives. 1 Parents can play a key role in the development of children's anxiety symptoms 2 ; yet, the evidence of parent-focused interventions is relatively thin. 3 This may be because little is known about what the optimal content of these interventions should be. Interventions typically either use parents as lay therapists, or target multiple different family risk factors at the same time. 4 Traditional randomized trials of these "package deal" interventions provide little insight into what specific parental risk factors should be targeted to most effectively reduce children's anxiety. 5 We will examine the effects of targeting distinct parental risk factors to provide more information on the role of these factors in children's anxiety, and to guide the development of intervention programs.