Low rates of participation in parenting interventions may undermine their effectiveness. Although a wide range of strategies to engage parents in interventions are described in the literature, little is known about which engagement strategies are most effective in enhancing parental engagement. This systematic review explores effective engagement strategies to encourage initial parental engagement (recruitment, enrolment, and first attendance) in parenting interventions for parents of children aged 2–8 years old. This review was conducted based on the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins and Green 2011) and the Preferred Reporting Items for Systematic Review and Meta-Analysis (Moher et al. 2009). Electronic systematic searches from January 1996 to August 2017 were conducted in PsycINFO, Scopus, ProQuest Social Sciences Journals, CINAHL, and PubMed databases. Eight studies met the inclusion criteria representing 1952 parents from four different countries. Of the engagement strategies tested in included studies (monetary incentive, setting, testimonial, advertisement, and engagement package), three strategies (advertisement, incentive, and engagement package) showed a significant effect on a stage of engagement, but none across stages. The low methodological quality of the selected studies limits their generalisability and thus provides limited evidence regarding effective engagement strategies to increase recruitment, enrolment, and first attendance rates in parenting interventions. There is a need for further, more methodologically rigorous, research evidence regarding how to engage parents more effectively in the early stages of parenting interventions.