Integration has evolved as a well-embraced discourse within theory and policy debates concerning the accommodation of newcomers. However, in today’s increasingly cosmopolitan cities of Europe planning for integration fails to properly address increasing diversity as it is often grounded in pre-conceived assumptions of traditional nation-state ideology around social and cultural homogeneity. Primarily focusing on policy measures like integration courses, compulsory language courses, citizenship exams, etc., the traditional approach imposes values of the ‘host country’ upon newcomers along with a strong national identity without considering positive aspects of their transnationality, and chance of mutual exchange between diverse individuals and communities. Such policies promote a deficit-based approach towards diversity through which perceptions of 'otherness', and 'insider versus outsider' mechanisms are perpetuated. Planning, as a policy field that deals with spatial organization, social justice and economic redistribution in cities, has a very little attempt to directly involve in the integration debate. Although the practice of planning has a lot to do with creating and sustaining the integration in neighborhoods and cities through social cohesion, the standard approach in planning for integration related matters is to provide social, spatial and economic infrastructure for the newcomers to blend into the surrounding society. In this approach, background of an individual is seen as a primary reason of failure or success, ignoring the multiple and constant interconnections across international borders. The present study argues that integration cannot be used as a one-type-fits-all model for dealing with diversity in today’s cosmopolitan cities where identities are more fluid, relational, and global in nature than collectively defined citizenship refers (Isin, 2000) and ‘difference is a daily reality’ (Bridge, 2005). Moreover, we argue, planning theory and practice should develop a comprehensive understanding of integration as part of spatial policy making in cosmopolitan cities. Thus, first of all integration should included and elaborated in planning theory as an important field dealing with social cohesion, and, while doing that, new approaches in urban planning and policy making are needed to respect different identities without eliminating differences between groups. The Toronto case shows that integration is directly included in the planning debate and in practice planning responds to the dynamic identities and cosmopolitan processes by redefining integration as a two way process. Based on semi-structured interviews with a range of actors involved in diversity-related urban policy-making (i.e. public officials, policy-makers and strategists at the federal, provincial and municipal levels, and non-profit organizations), and critical discourse analysis of city-wide documents, policy statements, and policy records, our findings demonstrate how integration can be included in urban planning and how the development and consolidation of more mutual and less assimilationist conceptions of integration within planning help improve diversity policy towards a more inclusive approach.