Many different terms are used to describe young people who are homeless, including including street youth, street kids, runaways, homeless youth, etc. Youth homelessness refers to young people between the ages of 13 and 24 who are living independently of parents and/or caregivers, and importantly, lack many of the social supports deemed necessary for the transition from childhood to adulthood. In such circumstances, they do not have a stable or consistent residence or source of income, nor do they necessarily have adequate access to the support networks necessary to foster a safe and nurturing transition into the responsibilities of adulthood.  

Over the course of the year the number of young people who wind up homeless is at least 35,000, and on any given night, there may be 6000 homeless youth.  Homeless youth may be temporarily living in hostels, staying with friends, living in 'squats', renting cheap rooms in boarding houses or hotels, or actually living on the streets. They may also be living with parents or relatives, but be at imminent risk of losing their shelter.  The reality is that over the course of time many homeless youth move between these various housing situations, thus it can be argued that it is the instability of their housing situation that characterizes their status as homeless youth.  

Youth homelessness is distinct from adult homelessness, both in terms of its causes and consequences, but also in how we must consider and apply interventions. Street youth, unlike homeless adults, leave homes defined by relationships (both social and economic) in which they were typically dependent upon adult caregivers, whether parents or relatives.  A high percentage of homeless youth were also in the care of child protection services. Becoming homeless then does not just mean a loss of stable housing, but rather leaving a home in which they are embedded in relations of dependence, thus experiencing an interruption and potential rupture in social relations with parents and caregivers, family members, friends, neighbours and community. For all of these reasons and more, a youth-based strategy – and the services that support this strategy – must be distinct from the adult sector.

The youth homeless population is also diverse. There are typically more homeless male youth than females (Segaert reports that 63% of youth in shelters are male, and 37% are female), which may be an outcome of the fact that young women are especially at risk of crime and violence (including sexual assault) while homeless, leading them to find alternatives to the streets, even if those alternatives pose other significant risks. Finally, certain significant sub-populations of youth are over-represented, including Aboriginal youth and in some cities like Toronto, black youth. Finally, youth who identify as lesbian, gay, bisexual, transgendered or transsexual (LGBTTQ) make up 25-40% of the youth homeless population, compared to only 5-10% of the general population

Age also matters when considering youth homelessness. Developmentally, there is a huge difference between the needs, circumstances, and physical and emotional development of a 14 year old compared to an 18 year old or a 23 year old (though it must also be acknowledged that the factors that produce and sustain youth homelessness – including violence, trauma and abuse, may also contribute to developmental impairment for older youth). 

While the category of homeless youth is marked by incredible diversity, what unites this population is its youthful age and lack of experience of independent living. This is important to consider because any response to homelessness – if it is to be effective – must address the causes and the conditions of homelessness. While there are some commonalities that frame the experience of homelessness for young people and adults – lack of affordable housing, systems failures in health care and corrections, for instance – there are important differences, including physical, mental, social and emotional development. Homeless youth typically lack the experience and skills necessary to live independently, and this is especially true for those under the age of 18. Moreover, the causes of youth homelessness are not necessarily the same as those that impact adults. Family conflict underlies youth homelessness, and many are fleeing abuse or leaving the care of child welfare services.