Access to psychological interventions for people under Crisis Resolution and Home Treatment Teams (CRHTTs) is limited. The Crisis Toolbox (CTB) is a skills-based intervention designed to increase access using flexible methods of delivery. This study aimed to evaluate the clinical effects of the CTB. A retrospective service evaluation of 399 participants who accessed the CTB between November 2020 and February 2021 was employed. Sessional measures comprising the Patient Health Questionnaire (PHQ-9) and Generalised Anxiety Scale (GAD-7) were recorded across three time points. Overall, there were significantly decreasing trends in PHQ-9 (β = - 1.6, p < 0.001) and GAD-7 scores (β = - 1.5, p < 0.001) in participants who accessed the CTB. The magnitude and direction of specific trends differed according to age, diagnosis, and neurodiversity. The CTB could help reduce depression and anxiety in people experiencing crisis. Randomised controlled trials are now required to test its acceptability, feasibility, and effectiveness.© 2023. The Author(s).