HabitWorks is a personalized, transdiagnostic, smartphone-delivered interpretation bias intervention. Our pilot studies of HabitWorks revealed good acceptability, feasibility, and target engagement in a variety of populations (Beard, Ramadurai, et al., 2021; Beard, Beckham, et al., 2021). Our next step is to test effectiveness for anxiety and depression symptoms in a larger, community sample. Results will provide pilot data to support an R01 effectiveness trial. We will randomize adults with anxiety or depression to HabitWorks or a credible control arm and examine effects on interpretation bias, symptoms, and functioning.