Twenty mothers participated in an online support group for parents of children with autism spectrum disorders. Twenty-five unrelated parents participated in a no-treatment control group. The participants completed online questionnaires prior to and following the 4-month support group, to evaluate changes in mood, anxiety, parenting stress, and positive perceptions. No significant differences between the groups or across time were found. However, parents who participated in the group reported being satisfied with the support they received and finding the group helpful. Issues related to participant recruitment and retention are discussed. Further research is required to investigate the efficacy of online support groups for parents of children with ASD.