This study explores the role of second units in the socio-economic integration of new immigrants living in the City of Mississauga, Ontario. Mississauga despite being a popular immigrant destination faces serious lack of affordable, social housing, and housing subsidies like many other Canadian cities. New immigrants generally face multiple barriers to access adequate and affordable housing here and often use illegal second units to fulfill their housing needs. The Province, owing to its inability to provide affordable, social, and increasing housing needs, is in the process of legalizing second units through Bill 140. espite their importance in immigrants' settlement process, there is virtually no research on this form of housing in the Canadian context. This study will fill this gap in the current literature. Moreover, it provides suggestions for the municipal government and civil society organizations to further alleviate barriers to the socioeconomic integration of new immigrants living in these units.