Behavioral inhibition (BI) is a temperamental style that poses risk for later anxiety. Efficacious interventions have been developed for inhibited children, but their success depends on parent engagement. However, little is known regarding predictors of parent engagement in early interventions for BI. This study examined parent-, child- and treatment-level (i.e., parent-only or parent-child) factors as independent and interactive predictors of parent engagement (attendance, and parent-reported homework completion and treatment satisfaction) in a randomized-controlled trial comparing two interventions for inhibited preschoolers (N = 151). Results suggest that child anxiety may motivate parent engagement, particularly when children receive concurrent treatment and/or in-vivo coaching. However, intensive treatment may be too burdensome for depressed parents, whereas less intensive treatments may be more acceptable to non-anxious parents of anxious children.