Yoga is an embodying activity that promotes body awareness, body connection, body responsiveness, and appreciation of body functionality, and it therefore may be a beneficial school-based intervention for children's body image. The present study examined the impact of a 4-week yoga intervention on pre-adolescent girls' and boys' body image (body appreciation, body esteem, and body surveillance) and mood (positive and negative affect) 1-week post-intervention and at 6-week follow-up. British children (N = 344; 54.4% female) aged 9-11 years were recruited from four schools, two of which were randomly assigned to the yoga intervention and two to a physical education control condition. Overall, girls reported greater body image concern and negative mood than boys. Unexpectedly, both groups reported increased body appreciation, body esteem, and positive mood, and decreased body surveillance and negative affect from baseline to post-intervention and/or follow-up. Both girls and boys in the yoga intervention evaluated the sessions very favourably; the majority desired to participate in more lessons. Potential explanations for these findings are discussed.