The article is organized into two main parts. First, it presents the termination of the conflict in Sierra Leone as a case-study to examine the degree to which cosmopolitan values connecting peacekeeping and peacebuilding are (or are not) evident. The case-study looks at the United Nations Mission in Sierra Leone (UNAMSIL) as a model of successful peacekeeping in the sense that everyday security was provided for the people of Sierra Leone through the deployment of a robust peacekeeping mission. This assessment needs to be qualified in relation to serious deficits still to be addressed in post-conflict peacebuilding, yet the success of this mission does provide encouragement for those who see the construction of a cosmopolitan security architecture for Africa as both desirable and achievable. Second, it explores the degree to which an appropriate model of cosmopolitan peacekeeping might emerge at regional and continental levels in Africa through the development of the African Standby Force (ASF). What the case-study presented here and the survey of the African Union (AU)/ASF in the second part of the article have in common is that taken together, they provide some evidence to suggest that, however fragile, the AU is beginning to define an agenda that represents a continent wide and, in that sense at least, a cosmopolitan response to African security issues.