Importance: Theory of mind (ToM) can be divided into two constructs: capacity and performance. Although severity of autism traits and verbal comprehension have been identified as being associated with ToM capacity, no study has yet verified their role in predicting the ToM performance of children with autism spectrum disorder (ASD). Objective: To examine the differences and associations between ToM capacity and ToM performance and to verify the role of autism traits and verbal comprehension in predicting ToM performance in children with ASD. Design: Cross-sectional study. Setting: Pediatric rehabilitation hospitals and clinics. Participants: One hundred four children with ASD who met the inclusion criteria. Outcomes and Measures: We examined ToM capacity and ToM performance with the Theory of Mind Task Battery (ToMTB) and the Theory of Mind Inventory-2-Chinese version (ToMI-2-C). Severity of autism traits and verbal comprehension were assessed with the Social Responsiveness Scale, Second Edition (SRS-2), and the Verbal Comprehension Index (VCI) of either the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition or the Wechsler Intelligence Scale for Children-Fourth Edition. We conducted correlation and hierarchical regression analyses. Results: Scores on the ToMI-2-C were significantly correlated with those on the ToMTB, SRS-2, and VCI (rs = .613, -.344, and .566, respectively; p < .01). Conclusions and Relevance: ToM capacity is significantly correlated with ToM performance. Both severity of autism traits and verbal comprehension played an important role in predicting ToM performance of children with ASD after controlling for ToM capacity.