There are vast numbers of children and youth in the world who find themselves connected to the streets. Owing to the difficulties of counting and defining this very fluid population, no accurate estimates exist on the numbers of children and youth spending a portion or majority of their time on the streets; however, they are estimated to be in the tens to hundreds of millions.

A variety of definitions have been put forth to define children and youth with street connections. Previously, the United Nations Children’s Fund broadly defined these children and youth as “[a]ny girl or boy who has not reached adulthood, for whom the street in the widest sense of the word, including unoccupied dwellings, wasteland, and so on, has become his or her habitual abode and/or source of livelihood, and who is inadequately protected, directed, and supervised by responsible adults.” A further categorization placed these children living and working on the street into 3 categories: children of the street (those who spend both days and nights on the street with limited or no family contact), children on the street (those who spend a portion or majority of their time on the street while returning home to a family/guardian at night), and children from street families (children from families living on the streets).1 In very high-income settings, youth connected to the streets are typically defined by their residential instability and precarious living arrangements, and they are referred to as homeless youth, runaway youth, system youth, or throwaway youth. Most recently, the term street-connected children and youth has been used to refer to those for whom the street is a central reference point—one that plays a significant role in their everyday life. While no clear definition encompasses the situations of all children and youth connected to the streets, it is important to understand that their circumstances are fluid and that the streets play a central role in their lives. It is also important to understand that children and youth connected to the streets are rights holders who often find themselves in situations that violate their basic human rights.

It is suspected that the dynamics driving this phenomenon (ie, street involvement of children and youth) are diverse and consist of complex pathways that vary between developed and developing countries, within geographic regions, by sex and age. However, the literature lacks any systematic compilation of children and youth’s reported reasons for street involvement, and there is an absence of consensus among academics, policy makers, stakeholders, and international organizations regarding these factors. Without empirical data on these reasons, policies are developed or implemented to mitigate street involvement without taking these causes into account. Often in resource-constrained settings, the prevailing paradigm assumes that children on the street are predominantly juvenile delinquents, and the government response is often characterized by social exclusion, criminalization, and oppression by police and civic authorities. Strategies frequently involve violent street sweeps conducted by police with children being placed in overcrowded detention centers or repatriated to unsafe care environments. Many of these children subsequently return to the streets. Resource-constrained settings typically lack well-established child protection systems, resulting in weak policies to mitigate children’s street involvement. In developed regions, child protection systems may be better equipped and able to respond to street youth with policies, legislation, and programs coordinated by government and nongovernmental agencies; yet despite this, children and youth in developed regions continue to find themselves in street circumstances.

Globally, street-connected children and youth have significant morbidity and mortality. To develop effective evidenced-based international and national policies aimed at preventing and mitigating the harms associated with street involvement, upholding children’s rights, and ameliorating the circumstances of the world’s most vulnerable children and youth, it is crucial to have rigorous evidence to comprehend this phenomenon. This review aims to systematically analyze the self-reported reasons why children and youth around the world become street-involved and to analyze the available data by level of human development, geographic region, and sex.