Delayed language development may be an early indicator of autism spectrum disorder (ASD). Early intervention is critical for children with ASD, and the present study presents pilot data on a clinical trial of omega-3 and -6 fatty acid supplementation and language development, a secondary trial outcome, in children at risk for ASD. We randomized 31 children to receive an omega-3 and -6 supplement or a placebo for 3 months, and measured their language abilities at baseline and after supplementation. Gesture use, but not word production, increased for children in the treatment group more than children in the placebo group. These results suggest possible effectiveness of omega-3 and -6 supplementation for language development in children at risk for ASD.