This report describes the challenges, successes, and outcomes of a nine-year project to enhance sustainable seasonal and pandemic influenza vaccine development in low- and middle-income countries globally. PATH, in collaboration with the World Health Organization and the Biomedical Advanced Research and Development Authority within the US Department of Health and Human Services, provided technical support to vaccine manufacturers in Brazil, China, India, Serbia, Thailand, and Vietnam as they worked to develop, manufacture, and submit for licensure safe and effective influenza vaccines.