Prosody production atypicalities are a feature of autism spectrum disorders (ASDs), but behavioral measures of performance have failed to provide detail on the properties of these deficits. We used acoustic measures of prosody to compare children with ASDs to age-matched groups with learning disabilities and typically developing peers. Overall, the group with ASD had longer utterance durations on multiple subtests on a test of prosodic abilities, and both the ASD and learning disabilities groups had higher pitch ranges and pitch variance than the typically developing group on one subtest. Acoustic differences were present even when the prosody was used correctly. These findings represent differences in the fine details of the acoustic output beyond its functional interpretation in "both" clinical groups.