Globally, debates on the notion of a third set of activities aimed at linking higher education institutions more closely with surrounding society are not new. In the last decade or so, calls for a re-engagement of the university in helping to tackle the great challenges facing societies and local communities have propelled the third mission to the forefront of policy discussions--this time under the mantra of "relevance" and "social impact". Yet, as some of the articles in this special issue attest, there is a fundamental tension in the notion of a third mission. The chief aim of this special issue is to provide a critical assessment of the extent to which the third mission has become an integral part of universities' core structures and primary activities--from the perspective of institutionalization. The individual contributions provide different accounts and perspectives on internal developments surrounding the third mission, but they all share the notion that major tensions and volitions surrounding its institutionalization remain largely unresolved.