The Internet offers many opportunities to provide parenting support. An overview of empirical studies in this
domain is lacking, and little is known about the design of web based parenting resources and their evaluations, raising questions about its position in the context of parenting intervention programs. This article is a systematic review of empirical studies (n = 75), published between 1998 and 2010, that describe resources of peer and professional online support for parents. These studies generally report positive outcomes of online parenting support. A number of recent experimental studies evaluated effects, including randomized controlled trials and quasi-experimental designs (totaling 1,615 parents and 740 children). A relatively large proportion of the studies in our sample reported a content analysis of e-mails and posts (totaling 15,059 coded messages). The results of this review show that the Internet offers a variety of opportunities for sharing peer support and consulting professionals. The field of study reflects an emphasis on online resources for parents of preschool children, concerning health topics and providing professional support. A range of technologies to facilitate online communication is applied in evaluated Web sites, although the combination of multiple components in one resource is not very common. The first generation of online resources has already changed parenting and parenting support for a large group of parents and professionals. Suggestions for future development and research are discussed.