The Critical Role of Supply Chains in Preventing Human Immunodeficiency Virus Drug Resistance in Low‐ and Middle‐Income Settings

&NA; The functioning of the supply chain may be a driving factor behind the development of human immunodeficiency virus (HIV) drug resistance (HIVDR) in many low‐ and middle‐income countries (LMICs). Additionally, the effectiveness of supply chains will likely impact the scale‐up of both viral‐load monitoring and HIVDR testing. This article describes the complexities of global supply chains relevant for LMICs and presents early data on stock‐outs and drug substitutions in several countries supported by the US President's Emergency Plan for AIDS Relief. Supply chain systems will need to be strengthened to minimize interruptions as new antiretroviral therapy regimens are introduced and to facilitate adoption of new laboratory technologies.