This study aimed to assess physiological arousal and behavioral regulation of emotion in the context of frustration in 29 children with Autism Spectrum Disorders (ASD) and 45 typically developing children (41-81 months). Heart rate was continuously measured and emotion strategies were coded, during a locked-box task. Results revealed increases in arousal followed by a decline during recovery, significant for both groups indicating that heart rate patterns between groups were identical. The ASD group deployed less constructive and more venting and avoidance strategies, which was related to language impairments. We conclude that rather than abnormal levels of emotional arousal, a key impairment in young children with ASD may be difficulties in behaviorally regulating and expressing experienced emotions to others.