This study examined whether children clinically referred for gender dysphoria (GD) show increased symptoms of autism spectrum disorder (ASD). Circumscribed preoccupations or intense interests were considered as overlapping symptoms expressed in GD and ASD. In gender-referred children (n = 534; 82.2% male) and their siblings (n = 419; 57.5% male), we examined Items 9 and 66 on the Child Behavior Checklist, which measure obsessions and compulsions, respectively. Non-GD clinic-referred (n = 1,201; 48.5% male) and nonreferred (n = 1,201; 48.5% male) children were also examined. Gender-referred children were elevated compared to all other groups for Item 9, and compared to siblings and nonreferred children for Item 66. A gender-related theme was significantly more common for gender-referred boys than male siblings on Item 9 only. A gender-related theme was not significantly more common for gender-referred girls compared to their female siblings on either item. The findings for Item 9 support the idea that children with GD show an elevation in obsessional interests. For gender-referred boys in particular, gender-related themes constituted more than half of the examples provided by their mothers. Intense/obsessional interests in children with GD may be one of the factors underlying the purported link between GD and ASD.