Placement instability in residential youth care is an important issue. Youth in residential care have the highest number of previous placements compared to youth in other types of out-of-home care (e.g., foster care), and the high number of previous placements can be experienced as traumatic events. Placement instability is associated with negative outcomes for youth, such as mental health problems. However, there is no review of the factors associated with placement instability in residential care. In this study, we reviewed research (qualitative and quantitative) on factors related to placement instability in residential youth care. A search in four databases (PsycINFO, ERIC, SocINDEX, and Medline) resulted in 10,299 hits. After selecting on the inclusion criteria, we included fifteen articles in our analysis. We identified several youth, family, decision-making, care, and, organizational factors associated with placement instability in residential care. In general, the number of studies focusing on placement instability is small. Most studies focused on static (i.e., unchangeable) youth factors, such as sex and age. We found some indications that dynamic (i.e., changeable) family, care, and organizational factors, such as poor parenting skills, low staff competence and turnover of professionals are positively associated with placement instability. It is striking that most of the included studies focused mainly on static youth factors. We need more knowledge about dynamic factors to reduce placement instability in residential youth care. Future research should focus on elements that might prevent placement instability.