This thesis is an interpretive inquiry into the effect of partnership work on the evolving role of social enterprises in England. Partnerships between social enterprises and public, private and third sector organisations are examined to determine how interorganisational relationships are framed and understood by social enterprises, what motivates their formation and how the hybrid identity of social enterprises is affected by partnership work. In-depth interviews were conducted with a selection of social enterprises in England where partnerships have become a distinct feature of social policy. The dynamics of this institutional environment provided rich examples of interorganisational relationships that were analysed to identify a typology of social enterprise partnerships depicting three main types: mandated, commercial and self-directed partnerships. The existing multidisciplinary literature on partnerships, specifically theory and frameworks concerning social partnerships, are applied to develop this typology throughout the thesis. Recent developments in social enterprise theory, namely the theoretical framework developed through the work of the ICSEM project, are also integrated to explore whether and how the origin of certain types of social enterprise influences their partnerships. Conclusions suggest that working across institutional and sector boundaries poses significant challenges and risks for social enterprises, such as loss of autonomy and curtailment of social objectives. Greater attention must be paid by social enterprise scholars to the partnership phenomenon, to the lived experiences of social enterprises engaged in partnership work, and to the constantly shifting political and social context that promotes the promise of partnership without acknowledging how it may curtail the unique capabilities of social enterprises.