Background: Originally designed for use with adolescents in group-based settings, there has been limited evaluation of Trauma and Grief Component Therapy (TGCT) with respect to its use with individual patients across a wide age range of children and adolescents. Objectives: This study describes a pilot open trial of individually administered TGCT, an assessment-driven, modularized treatment for traumatized and/or bereaved children and adolescents. Key outcomes measures include posttraumatic stress, depressive symptoms, and maladaptive grief reactions. Method: The sample consisted of 58 treatment-seeking children and adolescents who experienced trauma and/or bereavement (ages 7-17 years, M = 12.78, SD = 2.93; 68.4% female; 45.6% Hispanic, 14.0% Black, 22.8% White, 14.0% Multiracial). The study used a single-group open trial design. Youth referred to the study due to experiencing a potentially traumatic event or death of a loved one completed self-report measures of posttraumatic stress, depressive symptoms, and maladaptive grief reactions (when applicable). Measures were also completed following Module 1 of the treatment. Results: Bayesian regression models revealed youth who completed TGCT Module 1 reported substantial reductions from baseline, with large effect sizes for posttraumatic stress, depressive symptoms, and maladaptive grief reactions. Rates of reliable improvement ranged from 42 to 65% across treatment outcomes with 69% of youth demonstrating reliable improvement in at least one outcome. Conclusions: The present study provides preliminary evidence supporting TGCT as an individual treatment for traumatized and/or bereaved children and adolescents experiencing posttraumatic stress, depressive symptoms, and/or maladaptive grief reactions.