This thesis proposes that dialogue should be seen as a core element of education, from practice to theory and research. The research arose from a concern, not for a generic concept of education but for specific educational practices in association to dialogue. When the focus of the analysis narrows on certain educational practices the association between dialogue and education becomes problematic. If education is seen as dialogue and if assessment is an educational practice then the association of dialogue to assessment should be reasonably straightforward. Yet this is precisely where a contradiction emerges that highlights that it should be possible to associate educational practices with dialogue but too often this is not the case. This research set out to examine the possibility of associating dialogue with assessment through the development of a set of dialogical principles derived from the literature and from professional experience in two contexts, namely Distance Education and conventional Third Level Education courses at undergraduate and post-graduate level. The research is a multi-phase study which utilises a Multi-faceted Design-Based research approach to investigate through cycles of design-implementation and evaluation two assessment interventions (a new feedback report form and a dialogically-oriented assessment portfolio) designed to infuse dialogical principles in assessment practice. The research undertaken for this thesis has led to the disclosure of the tri-dimensional nature of the association of dialogue with assessment. The thesis proposes that ontologically, assessment should be seen as dialogue, ethically it should act as a catalyst for dialogue, and methodologically this should be achieved in educational practice through dialogue, understood as multi-form method. A model of dialogically-infused assessment has been generated which, thanks to its non-prescriptive formulation, offers a flexible framework for practitioners who may wish to stir their assessment practice in a dialogical direction.