Policy brief. HIV self-testing (HIVST) is a convenient and confidential option for HIV testing. In 2016 WHO recommended HIVST as a safe, accurate and effective way to reach people who may not test otherwise, including people from key populations, men and young people. Lay users can perform HIVST reliably and accurately and achieve performance comparable to that of trained health-care workers. Globally, many countries have developed HIVST policies, and implementation is growing rapidly. This policy brief highlights new guidance to optimize HIVST implementation, including effective service delivery models, linkage to care and support tools.