Children thrive in stable and nurturing environments where they have a routine and know what to expect. Yet a large number of children face instability at some point in their lives. They experience change in individual or family circumstances that is abrupt, involuntary, and/or in a negative direction. This fact sheet highlights key findings from a review of research in five areas of instability: family income, parental employment, family structure, housing, and the out-of-home contexts of school and child care. It also discusses recommendations for policy and practice to alleviate instability's impact.