Online parenting programs to support parents of children with behavioral problems and emotional problems have become widely available in recent years. Research has consistently shown their positive effects on child development, parents' adaptive parenting practices, and parents' mental health. However, knowledge is lacking on which type of content is more suitable to be delivered online. Our work addresses this knowledge gap by conducting traditional and network meta-analyses to improve our understanding of (1) how effective online parenting programs are to improve children's behavior and emotional problems, and (2) what clusters of components are most likely to yield the strongest effects. Following the PROSPERO preregistration, we systematically searched PsycINFO, MEDLINE, Web of Science, and Cochrane. Of the 8292 records retrieved, 28 records on 27 randomized controlled trials (N = 5,312) met the inclusion criteria. Results show moderate effect sizes of online parenting programs on reduced child behavioral and emotional problems, parents' ineffective parenting practices, and parents' mental health problems. Online programs adopting a learning theory perspective, either with or without additional parental self-care and parents as therapist approaches, are most likely to yield the strongest effects on child behavioral problems. Online programs adopting a learning theory perspective, parental self-care and parents as therapist approaches, with or without additional relationship perspectives, are most likely to yield the strongest effects on child emotional problems. Online parenting programs seem promising tools for improving child behavioral and emotional problems. Future research should identify the circumstances that allow parents and children to benefit more from specific components in these programs.