["Journal of Child Psychology and Psychiatry, EarlyView. ", "\n\nBackground\nThis study evaluated the efficacy of three interconnected parenting seminars delivered online and through schools in promoting positive parenting practices and improving children's social, emotional and behavioural wellbeing.\n\n\nMethods\nThe study employed an incomplete batched stepped wedged cluster randomised trial design, which tests systematic replication of effects across different batches and steps and allowed schools to be recruited throughout the project. Parents (n = 912) of children aged 4–13 years (M = 7.91) from 160 primary schools in three Australian states were included in the evaluation. A comprehensive set of measures was administered at baseline, post‐intervention and follow‐up to track changes in child‐ and family‐related outcomes. Data analysis adopted an Intention to Treat (ITT) approach, and intervention effects were estimated with Latent Growth Curve Models (LGCMs).\n\n\nResults\nITT analyses showed significant improvements in positive parenting practices, parental adjustment and parental self‐regulation, as well as reductions in coercive parenting, child anxiety symptoms, emotional maladjustment, behavioural problems and peer relationship problems with small‐to‐medium effect sizes. Intervention effects were systematically replicated in seven randomly assigned cohorts. Null effects were found on measures of parental relationships and child depression symptoms.\n\n\nConclusions\nA universally offered, brief, low‐intensity, school‐based parenting seminar series can produce meaningful improvements in parents' reports of their parenting practices and parental self‐regulation, as well as their children's social, emotional and behavioural adjustment.\n\n"]