Parentification can be defined as the collapse of boundaries within the family system where the child assumes the parental role and begins to perform parental tasks. There are several definitions and dimensions of parentification, its operationalisations, and the measurement instruments used. The primary objective of this scoping review is to explore and clarify the multifaceted concept of parentification, encompassing its various definitions, types, dimensions, and implications within family dynamics, as well as its association with related concepts. The second objective is to critically evaluate the existing tools and methods used to measure parentification, focusing on their effectiveness in capturing the diverse aspects of parentification, including the differentiation between its types and dimensions. The Scopus and Web of Science databases were searched, and a total of 112 articles were analysed following PRISMA guidelines. The research analysed in this review conceptualises parentification through different dimensions: relationships and roles, forms of parentification, and predominantly negative consequences that affect a child’s mental health. Regarding measurement instruments, we can divide them into two groups. The first group consists of instruments that measure parentification as a separate construct with various aspects. The second group includes instruments that measure parentification as one dimension of the parent-child relationship, measured through the reversal of roles and the emotions connected with it. This review enhances understanding of parentification by offering a comprehensive synthesis of its definitions and dimensions. In addition, this review provides recommendations on which measurement instruments would be beneficial to use in research on parentification.