This thesis explores the relationship of the European Community/Union (EC/EU) and the Association of Southeast Asian Nations (ASEAN) within the context of five deduced functions of inter- and transregionalism: balancing, institution building, rationalising, agenda setting and collective identity formation. The objectives of the study are threefold. The first, at the micro-level, is to explore the relationship between the European Community/Union and ASEAN at the inter- and transregional level since its inception in the 1970s. Secondly, and related to the first, it is an objective to test, within the context of the EC/EU-ASEAN relationship, whether the framework of functions of inter- and transregional relations deduced by scholars are actually performed. Such an in-depth study of the performance of these functions has not previously been undertaken. Thirdly, at the macro-level, is the objective of supplementing the framework of functions of inter- and transregionalism by: (i) elaborating the nature of the functions performed in more detail than has so far been provided by scholars; and (ii) seeking to explain why these functions are or are not performed, or indeed are only partially performed, through the introduction of actorness as a moderating variable. This is governed by the working hypothesis that: the level of actorness ofthe regional groupings involved in any inter- or transregional dialogue or process will affect the extent to which, and the manner in which, the five deduced functions of such dialogues are performed.