This chapter provides a detailed analysis of the boundaries of friendships. It starts by showing how patterns of partnership, family and household constitution have changed, making kin relationships more contestable. However, it also argues that for most people the boundaries between family and friendship remain relatively well defined and continue to be important, although perhaps different emphases will emerge. It suggests that friendships are different from family relationships especially since the solidarities are different. Friendships, it contends, have boundaries that are fluid and more easily broken. So rather than conceptualising the boundary between family and friends as becoming intrinsically blurred, the discussion suggests instead that the forms of solidarity associated with ‘blood’ ties may now be found in other relationships.