Background: Taijin-Kyofu-sho, an East Asian culture-bound anxiety disorder, has been likened to social anxiety disorder. However, few studies have examined these two disorders from the perspective of neurodevelopmental disorders. This study aimed to examine the association of Taijin-Kyofu-sho and social anxiety disorder with attention-deficit/hyperactivity disorder and autism spectrum disorder.Methods: The Liebowitz Social Anxiety, Taijin-Kyofu-sho, and Adult Attention-Deficit/Hyperactivity Disorder Self-Report scales and the 16-item Autism-Spectrum Quotient were administered to 818 university students. Participants were divided into four groups: control (neither Taijin-Kyofu-sho nor social anxiety disorder), pure Taijin-Kyofu-sho (Taijin-Kyofu-sho alone), pure social anxiety disorder (social anxiety disorder alone), and Taijin-Kyofu-sho-social anxiety disorder mixed (both Taijin-Kyofu-sho and social anxiety disorder). We used logistic regression analysis to examine whether attention-deficit/hyperactivity disorder and autism spectrum disorder were associated with Taijin-Kyofu-sho and social anxiety disorder.Results: Autism spectrum disorder was significantly associated with pure Taijin-Kyofu-sho (p = 0.006, odds ratio: 3.99). Female sex and attention-deficit/hyperactivity disorder were significantly associated with pure social anxiety disorder (sex: p = 0.013, odds ratio: 2.61; attention-deficit/hyperactivity disorder: p = 0.012, odds ratio: 2.46). Female sex, attention-deficit/hyperactivity disorder, and autism spectrum disorder were significantly associated with Taijin-Kyofu-sho-social anxiety disorder mixed (sex: p = 0.043, odds ratio: 2.16; attention-deficit/hyperactivity disorder: p = 0.003, odds ratio: 2.75; autism spectrum disorder: p < 0.001, odds ratio: 16.93). Conclusions: Neurodevelopmental disorder traits differed between individuals with Taijin-Kyofu-sho and those with social anxiety disorder. Japanese individuals with attention-deficit/hyperactivity disorder or autism spectrum disorder traits are at a risk of developing Taijin-Kyofu-sho or social anxiety disorder in the future.