This thesis presents an analysis of the relationship between grammatical agreement and so-called 'non-configurationality'. We argue that the properties of non-configurational languages should be made to follow from independently motivated principles of agreement. We explore the contrast, discussed in Hale (1989), between languages such as Navaho (Athapaskan) which permit cooccurrence of full noun phrases and agreement inflection and languages which show complementary distribution between these categories, such as Dogrib (Athapaskan) and Irish (Celtic). We argue that the study of these contrasts supports the analysis of non-configurationality presented in Jelinek (1984) where agreement morphemes have argumental, theta-marked status...