Aims: Developing and evaluating an email-based intervention (EBI) to enhance alcohol-related parenting skills and reduce alcohol consumption among adolescents. Methods: Over four weeks, participating parents received a weekly email containing scientific findings, practical advice and exercises in relation to such topics as alcohol-related rule-setting and communication. Using a randomised controlled trial (ID: DRKS00007763), data from 467 parents and 173 adolescents were collected via self-report online questionnaires and analysed by means of repeated measures analysis of variance. Findings: Controlling for baseline, parents in the intervention group (IG) scored higher for being informed (parents of girls: F = 19.023, p = 0.000; parents of boys: F = 30.294, p = 0.000) and for self-efficacy (parents of girls: F = 6.122, p = 0.014; parents of boys: F = 10.195, p = 0.002) at follow-up and, in the case of boys, were more successful in maintaining strict rules on alcohol consumption (F = 13.704, p = 0.000) than parents in the control group (CG) (girls: F = 1.627; p = 0.204). Boys whose parents were in the IG reported less heavy episodic drinking at follow-up (F = 4.192, p = 0.043), controlled for baseline, than those with parents in the CG (girls: F = 0.567; p = 0.454). Conclusions: The EBI has positive effects on alcohol-related parenting and may reduce heavy episodic drinking among boys. Since it is delivered via email, the programme has considerable potential to reach many parents at low cost.