Autism spectrum disorder (ASD) is an etiologically heterogeneous neurodevelopmental condition that eludes a single explanation or cure. Epidemiological studies reveal risk factors, relevant comorbidities, and behavioral correlates to reach a better understanding of ASD. To contribute such data from an understudied ASD population, this paper presents epidemiological data from a Turkish sample of individuals with ASD (n = 911, 748 boys (82.1%) and 163 girls (17.9%) between 1 and 18 years of age). Average age at diagnosis was 31.06 ± 11.88 months, and the male-to-female ratio was 4.6:1. Three in 4 individuals with ASD had obsessive behaviors, and 1 in 4 had allergic conditions, inappropriate sexual behaviors, self-harming behaviors, and harmful behaviors towards others. One in 3 received a dietary treatment for at least 3 months; almost half received vitamin supplements; the majority (70%) did not experience constipation; and 2 in 3 were picky eaters. This paper presents data on the age of diagnosis, gender ratios, accompanying behaviors, and dietary interventions in Turkish individuals with ASD, which are topics of current research interest about ASD. Such data from non-Western populations may supplement epidemiological knowledge gained from Western populations to help reach a more comprehensive understanding of this condition with many unknowns.