These guidelines to UNAIDS’ preferred terminology have been developed for use by staff members, colleagues in the programme’s 10 Cosponsoring organizations, and their partners working in the global response to HIV. Language shapes beliefs and may influence behaviours. Considered use of appropriate language has the power to strengthen the global response to the epidemic. UNAIDS is pleased to make these guidelines to preferred terminology freely available. It is a living, evolving document that is reviewed on a regular basis. Comments and suggestions for additions, deletions, or modifications should be sent to terminology@unaids.org. The boxed list (summary of preferred terminology) overleaf highlights the most important points that we recommend users follow. These guidelines may be freely copied and reproduced, provided that it is not done so for commercial gain and the source is mentioned.