Finnish national data sets on schools (N = 496) and pupils (N = 74,143; 14-16 years) were used to study whether a systematic documenting policy for the violations of school smoking bans was associated with pupils' smoking and their perceptions on the enforcement of smoking bans. Attending a school with a systematic documenting policy was associated with perceptions that smoking is prohibited and restrictions monitored, with lower levels of smoking in the vicinity of the school during the school day, but not with smoking prevalence. Findings suggest that a consistent documenting policy could be an effective tool for reducing pupils' smoking in schools.