Lee, ChiThis document examines the string duo repertoire with viola from the beginning of the genre in the 18th century to the present day. The study begins by documenting over 3,000 string duos with information regarding the composers, time periods, publishers, and instrumentation. A table including the information of all known string duos with viola is included with as many details as possible to present a complete representation of the repertoire that exists. The information gathered from this data will then be analyzed to find general trends in the compositions from the Baroque, Classical, Romantic, and Modern periods. Upon examining different pieces in more detail, the performance practice and techniques required from the viola will be explored to better understand how composers used the viola in string duos throughout history.enDissertationMusic