Early childhood development is increasingly recognized as a key public issue. Parenting interventions form an important evidence-based strategy to foster infant-toddler cognitive and language skills, motor and socio-emotional development and adaptive behavior. This systematic review investigated the effectiveness of group-based parenting interventions focused on families with children about 0-2 years old, living in vulnerable populations. As well as children development assessments, parenting skills, attitudes and knowledge were examined as outcomes. A range of databases were systematically searched and randomized trials and quasi-experimental approaches included. Fourteen studies with 4,082 parents of babies and toddlers, in nine countries, reported findings which favored interventions on a range of parenting measures and children outcomes, though some studies show mixed results. There is a great heterogeneity in terms of the length of the intervention, the qualifications requires for the instructors and the program components that accompany the group intervention. Thus, it is crucial to assess the cost of each intervention to evaluate the feasibility of its implementation in a developing country with scarce resources. Most of the studies included lacked this cost analysis.