Digital well-being concerns the balanced and healthy use of digital technology, and the existing studies in this area have focused on adolescents and adults. However, young children are more vulnerable to digital overuse and addiction than adults; thus, their digital well-being deserves empirical exploration. In this scoping review, we synthesized and evaluated 35 collected studies on young children's digital use and their associated well-being that were published up to October of 2022 to understand the related definitions, measurements, contributors, and interventions. The synthesis of the evidence revealed that (1) there was no consensus about the definition of the concept of digital well-being; (2) there were no effective ways of measuring young children's digital well-being; (3) both child factors (the duration and place of digital use, as well as the child's demographic characteristics) and parent factors (digital use, parental perception, and mediation) contribute to young children's well-being; and (4) there were some effective applications and digital interventions reported in the reviewed studies. This review contributes to the development of this concept by mapping the existing research on young children's digital well-being, as well as proposing a model and identifying the research gaps for future studies.