INTRODUCTION: Online-based interventions provide a low-threshold way to reach and support families. The mentalisation-based Lighthouse Parenting Programme is an established intervention aimed at preventing psychopathological development in children. The objective of this study is to examine the feasibility of an online adaptation of the Lighthouse Parenting Programme (LPP-Online), evaluating (a) recruitment capability, compliance, acceptability and satisfaction with the intervention; (b) …