Children with autism spectrum disorder often demonstrate difficulties with self-regulation, although studies of this construct in young children with autism spectrum disorder are limited. In this study, developmental changes were examined using a measure of self-regulation appropriate for young children, resistance to temptation. At 22, 28, and 34 months, toddlers with an older sibling with autism spectrum disorder (high risk) and toddlers with typically developing older siblings (low risk) were presented with an appealing toy and instructed not to touch it. Observers coded whether or not children touched the toy and the strategies they used to resist touching it. At 36 months, children were assessed for autism spectrum disorder, yielding three groups: high risk children with autism spectrum disorder, high risk children without autism spectrum disorder, and low risk children. At 22 months, most children, regardless of group, touched the forbidden toy; at 28 and 34 months, many high risk children without autism spectrum disorder and low risk children resisted the temptation to touch the toy, whereas most of the children with autism spectrum disorder did not. Differences in delay strategies were also evident. Some, but not all group differences, were accounted for by differences in language ability. Results highlight one early index of impulse control that differentiates children with emerging autism spectrum disorder from age-mates prior to the third birthday.