This systematic review updates the global prevalence of autism, synthesizing estimates from 71 studies published since 2012. The median prevalence of autism is 100 per 10,000 (range: 1.09 to 436.0 per 10,000), with a male-to-female ratio of 4.2. The median percentage of autism cases with co-occurring intellectual disability is 33%. Prevalence estimates vary across regions and sociodemographic groups, reflecting complex interactions between community awareness, service capacity, help-seeking behaviors, and sociodemographic factors. The review highlights an increase in measured autism prevalence globally, attributed to factors such as increased community awareness, public health response, progress in case identification, and broader diagnostic criteria. The findings also suggest that social determinants like biological sex, sociodemographic status, ethnicity/race, and nativity may influence autism prevalence, though the mechanisms are complex and require further research. The review underscores the need for improved methods and larger, representative samples to better understand the underlying etiology and social determinants of autism.This systematic review updates the global prevalence of autism, synthesizing estimates from 71 studies published since 2012. The median prevalence of autism is 100 per 10,000 (range: 1.09 to 436.0 per 10,000), with a male-to-female ratio of 4.2. The median percentage of autism cases with co-occurring intellectual disability is 33%. Prevalence estimates vary across regions and sociodemographic groups, reflecting complex interactions between community awareness, service capacity, help-seeking behaviors, and sociodemographic factors. The review highlights an increase in measured autism prevalence globally, attributed to factors such as increased community awareness, public health response, progress in case identification, and broader diagnostic criteria. The findings also suggest that social determinants like biological sex, sociodemographic status, ethnicity/race, and nativity may influence autism prevalence, though the mechanisms are complex and require further research. The review underscores the need for improved methods and larger, representative samples to better understand the underlying etiology and social determinants of autism.