This thesis serves to provide insight into the interpretation and performance of Rebecca Clarke’s Sonata for Viola and Piano (1919). To provide context to the analysis and interpretation, the life and work of Rebecca Clarke (1886-1979) is described. The viola sonata is analysed in terms of harmony, colours and technical elements for the purpose of aiding the interpretation and performance. The sonata is also cross referenced with other works by the same composer, to further pinpoint the stylistic elements and their importance for the result. From the analysis it is concluded that the common elements in Clarke’s music and in the sonata in particular, include modality, harmonic ambiguity, polytonality and a range of instrumental techniques. The meticulous notation and the overall instrumental ergonomics of the piece shows both that Clarke had a clear vision for her music, and that she knew the nature of both the viola and the piano well. In conclusion, I argue that in order to present a captivating performance of the piece, great care must be taken to the distinction and sensitivity of these elements in particular.