Every year 14% of children in Australia develop serious emotional or behaviour problems that can have detrimental long-term effects for the children themselves, for their families and for society.Behavioural family interventions are effective in the prevention and treatment of these problems, but have not yet had large-scale societal impact because only a small proportion of families actually receive evidence-based interventions. To address this problem, parenting programs need to be made available at different levels of intensity, across a variety of settings and in a variety of formats. One increasingly accessed forum for parents is the Internet, however, little is known about the potential of web-based programs to strengthen parenting. This thesis argues that one way to improve parents' access to parenting programs is by offering a low-intensity, self-directed online parenting program.To date no such intervention has been evaluated for parents of children with behaviour problems.This series of research is comprised of three empirical studies: 1) a consumer survey seeking to establish the feasibility of online parenting support for a broad range of parents; 2) a randomised controlled trial testing the efficacy of a brief online parenting program (Triple P Online Brief [TPOL Brief]) in reducing dysfunctional parenting and child behaviour problems; and 3) an investigation of the predictors of use and outcomes of TPOL Brief.Chapter 1 reviews the relevant literature and provides a rationale for the current research series. The role of parenting interventions in the prevention and treatment of child behaviour problems is examined and their current limitations are discussed. Evidence for the efficacy of various intervention formats is reviewed, and brief, low-intensity online parenting programs as part of a public health approach are proposed as a way of broadening the reach of parenting interventions.The chapter highlights challenges and unanswered questions regarding online parenting support and describes the study aims.Chapter 2 presents data from a cross-sectional survey of 459 Australian parents of 2-12 year old children. The survey examined 1) parents' access to and use of the Internet, 2) parents' use of different sources of parenting information, especially online sources, and 3) preferred delivery modalities for receiving information about parenting. In order to investigate if online parenting support favours well-educated, middle class families or is suitable for a broad range of parents, the study examined the extent to which use of web-based parenting information and perceived usefulness ratings of online programs could be predicted by a range of variables, in particular families' socio-demographic characteristics. Results indicate that the majority of parents use parenting websites (65%) and social media (45%) for parenting information and that providing iii parenting support online may be a viable way to reach a broad range of families, even those typically less likely to access other forms of...