The purpose of this study was to investigate stuttering prevalence in Flanders, the northern part of Belgium. Using questionnaires distributed among teachers, data were collected on 21,027 pupils from regular schools (age between 6 and 20 years) and 1,272 pupils attending special education (age between 6 and 15 years). The overall prevalence in the regular school population was 0.58%. It was 2.28% in the special school population. In agreement with past studies, stuttering prevalence was higher in males than in females, and higher in pupils attending special schools than in pupils from regular schools. The tendency for stuttering prevalence to decrease with increasing age was confirmed too, but not in the pupils of special schools. Additionally, the pupils of regular schools showed a pattern that was contrary to the general belief that the male-to-female ratio in stuttering prevalence increases with age. Results further indicate that the commonly cited stuttering prevalence figure of 1% is a generalization that requires interpretation.