Since its operational beginnings in the United States in 1982—where its prototypes were first experimented with in the 1960s and 1970s—the electronic monitoring (EM) of offenders has spread to approximately 40 countries around the world, ostensibly—but not often effectively—to reduce the use of imprisonment by making bail, community supervision, and release from prison more controlling than they have hitherto been. No single authority monitors the development of EM around the world, and it is difficult to gain fully comprehensive accounts of what is happening outside the Western and Anglophone users of it. Some countries are secretive. Standpoints in writing on EM are varied and partisan. Although it still tends to be the pacesetter of technical innovation, the United States remains a relatively lower user of EM, in part because the exceptional punitiveness of its penal culture has inhibited its expansion, even when it has itself been developed in various punitive ways. Interprofessional and intergovernmental processes of “policy transfer” have contributed to EMs spreading around the world, but the commercial bodies that manufacture and market EM equipment have been of at least equal importance. In Europe, the Confederation of European Probation (CEP), a transnational probation advocacy organization, took an early interest in EM, and its regular conferences became a touchstone of international debate. As it developed globally, the United Nations reluctantly accepted that it may be of some value even in developing countries and set out standards for its use. Continuing innovations in EM technology will create new possibilities for offender supervision, both more and less punitive, but it is always culture, commerce, and politics in particular jurisdictions which shape the scale, pace, and form of its development.