This chapter examines the rise of marketisation in criminal justice and the increasingly important role of third sector organisations in these markets. The authors give a brief history of criminal justice marketisation and the roles in it for various state and non-state entities. They then focus specifically on third sector agencies, defined as non-state, non-private sector bodies such as charities, not-for-profit groups, and voluntary organisations and individuals. This is followed by a survey of the types and extent of third sector involvement in contemporary criminal justice and key current trends. They examine the advantages and disadvantages of this development, before finishing with a brief discussion of implications for the future of criminal justice.