Parental alienation is a family dynamic in which a child rejects a parent without legitimate justification and has a strong alliance with their other parent. Parental alienating behaviours, such as one parent preventing contact between the other parent and child, are enacted over time with intent to harm the parent-child relationship. Alienated children display characteristics such as psychological splitting and a lack of guilt that help differentiate them from children who have been estranged and have legitimate reasons for rejecting a parent (e.g., the parent was abusive). Alienated children and parents suffer many poor outcomes such as depression, social isolation, and suicidality. Assessment tools and treatment models have shown promise in circumventing the negative effects of parental alienation on individuals’ health and well-being.