Body dissatisfaction is prevalent among adolescents and a primary risk factor for eating disorders, yet there are few body image interventions for older adolescents that support development of positive body image. Therefore, we assessed the feasibility, acceptability and preliminary effectiveness of BodyKind, a four-lesson, mixed gender, teacher-led, school-based curriculum for older adolescents, that combines principles of self-compassion, compassion for others, cognitive dissonance, and social activism to address contemporary adolescent body image concerns (i.e., appearance bias, comparisons on social media) and strengthen positive body image development. The sample contained 147 adolescents, predominantly racial/ethnic minorities (>95%), 54.8% male, 41.5% female and 4.1% gender-minority students aged 15-18 years (M=16.24, SD=.96) from a low-income, inner-city high school in the Midwestern US. Two teachers received training and delivered the curriculum to students. This single arm, mixed methods trial assessed student and teacher acceptability, teacher fidelity and student intervention outcomes. Despite reasonable teacher fidelity, recruitment/attendance rates, post-intervention data loss (35% attrition) limited evaluations of program effectiveness and study feasibility. Important learnings regarding study feasibility will inform optimisation for future school-based trials. Findings demonstrate high acceptability of BodyKind among teachers and adolescents in a lower socioeconomic school setting, and further randomized controlled effectiveness trials are required.