Studies have demonstrated the importance of informal social relationships in lone mothers’ everyday lives, not least regarding their ability to reconcile paid work and care duties. This paper examines lone mothers’ relationships with their friends. Drawing on qualitative interviews with Swedish lone mothers, it aims to analyse how friendship relations are described by the lone mothers, to what extent they are characterized by different forms of reciprocity and if the mothers perceive their friends as being part of their families. Inspired by Alberoni’s thoughts on friendship, and Finch and Mason’s view of reciprocity, the analysis reveals a complex picture of friendship relations. It is argued that friends often play a significant role in the everyday lives of the lone mothers. Friends were seen as key elements in some mothers’ lives, and sometimes were defined as ‘family’, providing emotional as well as practical support; but they were almost entirely absent in the lives of others. The support from their friends was often surrounded by norms of reciprocity. The results indicate that although the help from friends sometimes was decisive and appreciated, the mothers found it difficult to ask friends for help.