The concept of “child welfare” is a legal term, yet due to its nature and significance in the practices of judicial authorities, it falls within the sphere of interest for representatives of other academic disciplines as well, including psychology, pedagogy, and sociology. The legislation does not provide a definition of “child welfare”, which is a deliberate choice by legislators, emphasizing thereby the flexibility in shaping the legal situation of a child. However, this may pose practical challenges for courts of justice and psychologists collaborating with them in court proceedings. In the absence of a legal definition, there is a risk of excessive subjectivity in assessing the welfare of a child in a given factual situation. Hence, there is a need for specification by creating a definition or criteria for child welfare. This article undertakes a literature review to explore theoretical models and studies that explain the understanding of the aforementioned concept. The presentation of an answer to the question of what constitutes a child’s welfare and what serves their best interest began with an elaboration of three discourses about the concern of a child. Subsequently, selected models explaining child welfare are presented from a psychological perspective, accompanied by a description of the criteria based on the literature and law regulations. Drawing upon empirical studies cited in the final part of the article, a description and an explanation of the concept of “child welfare” were constructed within the broader context of related disciplines in the field of psychology and social sciences – namely, pedagogy and sociology.