Aggressive behaviors of children with autism spectrum disorder (ASD) are common. We conducted this study to describe the aggressive mode of preschool children with ASD and examine the associations between specific aggressive behaviors and two treatable factors: sleep problems and attention deficit hyperactivity disorder (ADHD) symptoms. In total, 577 typically developing (TD) children and 490 children with ASD were investigated in this study. The Institute for Basic Research – Modified Overt Aggression Scale (IBR‐MOAS) was used to assess aggressive behaviors. Children's social impairments, sleep problems and ADHD symptoms were also measured with specific scales. The total IBR‐MOAS score was significantly higher (worse) in the TD group [4.47 (5.36)] than in the ASD group [3.47 (5.63), P = 0.004]. The aggressive modes differed between groups: when compared with each other, the TD group received higher scores on Verbal and Physical Aggression Toward Others (all P < 0.01), while the ASD group had higher scores on Physical Aggression Against Self (P = 0.006). The linear regression model demonstrated that the aggressive behaviors of children with ASD were significantly associated with two treatable factors: sleep problems and ADHD symptoms. These findings have substantial clinical implications: treatment of these two risk factors may be helpful in managing aggressive behavior in children with ASD. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.