<p>Approximately 25% of children and adolescents diagnosed with a neurodevelopmental disability or psychiatric disorder are estimated to exhibit hoarding behavior. Challenging behavior may occur when opportunities to hoard are restricted. Both hoarding behavior and the associated challenging behavior may be concerning in these cases. The purpose of this study was to functionally analyze and treat challenging behavior reportedly evoked by disrupting control over hoarded items. We conducted practical functional analyses and skill-based treatment with two adolescents who reportedly engaged in both challenging behavior and hoarding behavior. A functional relation between hoarding and challenging behavior was demonstrated across two participants and three functional analyses. Challenging behavior and concerning hoarding responses were eliminated by the end of treatment, and both participants acquired multiple functional skills without behavioral escalation or signs of emotional distress. Results were demonstrated under lean reinforcement schedules in relevant contexts when typical caregivers implemented the intervention. Multiple strategies were incorporated from the onset of treatment to program for treatment effectiveness and to minimize behavioral and emotional escalation.</p>