This study is concerned with analysing the vocal and musical expression of the Alleluia as Gospel Acclamation in the Roman Rite Eucharistic celebration from a liturgical, vocal, and musicological perspective. There is, as of yet, no single comprehensive body of work on the Alleluia as a discrete musical-liturgical item. Two articles which treat the Alleluia in some depth, ‘Preface to the Study of the Alleluia’ by James McKinnon and ‘Acclamations: Our Ritual Voice of Faith’ by Aidan Rossiter, both note the poverty of research carried out on the subject to date, and point to the unanswered questions in relation to its provenance, development, and import in the liturgical celebration. I begin by consolidating and critique existing work on the historical origins of the Alleluia. This involves revisiting ‘alleluia’ in its original context, employing Biblical exegesis as an important methodology in examining the Scriptural origins of the Alleluia. Historical analysis forms a central role in tracing its retention from its original usage through to Byzantine, Gallican, and Roman liturgical developments. Contradictions regarding the assignment of the Alleluia as a Mass Proper and its controversial relationship with the jubilus of Patristic literature are presented and examined. This leads to a musicological analysis of Alleluia chant settings. The study then moves to an exploration of the role and function of the Alleluia as an affirmatory acclamation in the Roman Rite Eucharistic celebration. This involves an examination of liturgical items and their place in the liturgy, along with an exploration of the nature of ritual, and the concomitant place of sound in ritual practices. Finally, a musicological examination of Alleluia settings currently used in Irish Roman Rite Eucharistic celebrations, through an analysis of those in the national repertory, forms the basis of a case study, which gives us an insight into the acclamation in practice today, and the musical and liturgical considerations which aid its efficacy.