Indiscriminate friendliness (IF) refers to a lack of reticence with strangers and is well-documented in neglected children. This risky behavior is distinct from attachment insecurity, and persists when parenting/caregiving improves. A previous review has suggested that caregiving quality is not associated with IF. This review aimed to explore factors associated with IF and whether quality of caregiving is important. Ten articles were reviewed using the S.H. Downs and N. Black (1998) Checklist for randomized and nonrandomized studies. Overall quality was high. Results showed that IF is present in fostered populations and postinstitutionalized children. Attachment security was not associated with IF. Length of time in institution and inhibitory control were associated with IF. Inhibitory control moderated the association between IF and number of caregivers. Genetic factors predispose children to IF and may impact on persistence. Quality of caregiving was associated with IF. Emotional availability (i.e., the degree to which carer and child are able to respond to each other's emotional signals) predicted IF. Limitations across studies included heterogeneity in IF measurement and unreliable measures of preadoptive care. Parenting may be a useful target for intervention. Future research should focus on developing a standardized measure of IF as well as evaluating a parental intervention.