Abstract Background We examined a brief educational intervention addressing hand hygiene self-regulatory mechanisms, and evaluated which psychological mechanisms may lead to hand hygiene behaviours. Methods Two hundred forty two students (mean age = 21 years, SD  = 3.9) received either an experimental ( n  = 149) or a control condition on action control and planning ( n  = 93). Hand hygiene, coping planning, and action control were measured at baseline and six weeks later. By applying repeated measures ANOVA, we compared the experimental condition addressing planning to perform hand hygiene with a control condition. Additionally, working mechanisms were evaluated by means of mediation analysis. Results The intervention had an effect on action control, as reflected by a time by treatment interaction. The direct effect of the intervention on behaviour was, however, non-significant. Changes in action control led to changes in coping planning. These social-cognitive changes mediated the effect of intervention on behaviour, after controlling for gender, baseline behaviour, and classroom membership. Discussion In spite of the associations between the intervention and self-regulatory strategies, no direct effect was found of the intervention on behaviour. Further research on how to increase hand sanitizing, involving enviromental characteristics, is required. Conclusion The intervention led only indirectly to an improvement of hand hygiene via changes in self-regulatory factors. Results indicate the importance of promoting action control and coping planning to initiate changes in hand hygienic behaviours.