This study identifies and examines the patterns and provisions for girl choristers in eleven English cathedrals. Though some studies exist that discuss the physiological differences between boy and girl choristers and perceptions of their sounds, no study examines the structure of the choirs themselves. Significant changes had to be made to the music departments, personnel, and cultural ideas of cathedral music to make way for a separate line of choristers parallel to the traditional line of boy trebles and lay clerks. Prior to this wave of girl choristers, cathedrals did not typically need to examine or uproot their long-held musical structures. The normal choral routine of rehearsals, evensongs, matins, and Eucharist had been in place for centuries but applied to a single line of boy choristers singing with the men. With two lines of trebles, who will direct each group, and what will they sing, and when? Is this new line a full part of the ‘Cathedral Choir’ or are they ‘other’, something slightly less-than or a fringe voluntary group? Every cathedral had a goal in introducing a line of girl choristers, and this thesis posits that the way in which these questions, and others, were answered in each location speaks to that cathedral’s goal. Furthermore, whilst establishing the secondary line of girl choristers with exact parity to the existing line of boys is admirable, it is not necessarily a misogynistic statement to accept an uneven allocation of singing duties in the cathedral. Constraints such as financial resources and the structure of the choir school play a large role, and must be factored in to the policies set in place for a new line of choristers.