During a separation or a divorce, the child can be caught in the parental conflict and a conflict of loyalties may develop. In this context, and more specifically in a custody dispute, some parents may brandish the term "parental alienation syndrome" (i.e., the conscious or unconscious influence of one parent leading a child to denigrate and exclude the other parent and the latter's social network), a concept developed by Gardner (1985). However, this concept has been the subject of significant controversy and criticism. Lack of scientific basis, insufficient empirical data, or lack of diagnostic validity have led international organizations to reject its existence. Nevertheless, the term is used in civil courts of some European countries, as well as in the USA, Brazil, and Australia. In Switzerland, a petition aimed at recognizing “parental alienation syndrome” as a form of family maltreatment is provoking political debate and raising concerns among socio-judicial professionals, the justice system, and clinicians. This work reviews the history of this concept, its (lack of) evidence, criticisms and limitations, and its use in clinical and legal practice. This work concludes that, supported by clinical observations and scientific literature, the notion of loyalty conflict or divided loyalty should be preferred.