Imitation is an early skill thought to play a role in social development, leading some to suggest that teaching imitation to children with autism should lead to improvements in social functioning. This study used a randomized controlled trial to evaluate the effect of a focused imitation intervention on initiation of joint attention and social-emotional functioning in 27 young children with autism. Results indicated the treatment group made significantly more gains in joint attention initiations at post-treatment and follow-up and social-emotional functioning at follow-up than the control group. Although gains in social functioning were associated with treatment, a mediation analysis did not support imitation as the mechanism of action. These findings suggest the intervention improves social functioning in children with ASD.