Vaccine developers are required to submit a clinical trial application to the authorities in each country where a clinical trial will be conducted. The application has to be made both to the relevant Ethics Committees and to the National Regulatory Authorities, and only after appropriate clearance by both can a clinical trial commence. This paper describes two specific strategies, joint reviews of vaccine clinical trial applications and joint inspections of clinical trial sites by groups of countries, as part of a WHO initiative to strengthen capacity for the regulatory oversight of clinical trials in Africa. Significantly, the joint reviews and inspections contributed to reinforcing the capacities of the regulatory authorities as well as defining an efficient process to maximize the quality of the reviews and minimize undue delays. Finally we will suggest complementary mechanisms to overcome the potential limitations of joint reviews and inspections.