Some 1.5 billion people in the developing world lack proof of legal identity. This Identification Gap is a serious obstacle to participation in political, economic and social life. Without a secure and trustworthy way to prove their identity, a person may be unable to exercise the range of human rights set out in international laws and conventions. A lack of identification also makes it difficult to open a bank account, vote, obtain formal employment, access education or healthcare, receive a social transfer, buy a SIM card, or seek legal redress. Furthermore, states with weak identification systems have difficulty with government administration, planning, and service delivery, including collecting taxes, targeting social programs, responding to emergencies, disasters and epidemics, managing their borders, and providing security. Achieving inclusive development, therefore, requires a sustained effort to address the world’s identification gap. Digital technologies, such as cloud computing, biometrics, mobile networks and devices, and smartcards, can increase the security, accuracy, and convenience of identifying and authenticating individuals. As public and private service providers increasingly transition into the digital realm, the ability to prove who you are will be essential for participation in the digital environment. As a result, digital identification systems can create huge savings for citizens, governments, and businesses by reducing transaction costs, increasing efficiency, and driving innovation in service delivery, particularly to the poorest and most disadvantaged groups in society. With these opportunities, however, come important challenges and risks. Ensuring that all individuals are included in the system can be a huge challenge, particularly for remote and rural residents, the forcibly displaced, stateless persons, and other marginalized groups. Addressing these challenges is critical for ensuring that legal identification systems are effective and available to all end-users, the individuals who must prove their identity to access rights and services. This requires a coordinated, sustained effort by key stakeholders involved in the provision and use of these systems. A shared vision across the range of stakeholders, aligned through the set of common Principles, will help foster robust and inclusive identification systems that enable economic opportunities and sustainable development outcomes.