In light of the known visuoperceptual strengths and altered language skills in autism, we investigated the impact of problem content (semantic/visuospatial) combined with complexity and presence of lures on fluid reasoning in 43 autistic and 41 typical children (6–13 years old). Increased complexity and presence of lures diminished performance, but less so as the children’s age increased. Typical children were slightly more accurate overall, whereas autistic children were faster at solving complex visuospatial problems. Thus, reasoning could rely more extensively on visuospatial strategies in autistic versus typical children. A combined speed-accuracy measure revealed similar performance in both groups, suggesting a similar pace in fluid reasoning development. Visual presentation of conceptual information seems to suit the reasoning processes of autistic children.