Morpheus is a composition for viola and piano by the English composer and violist Rebecca Clarke. It was written in 1917 when Clarke was pursuing a performing career in the United States. The piece shows off the impressionistic musical language Clarke had developed, modeled on the music of Claude Debussy and Ralph Vaughan Williams, that is also apparent in her Viola Sonata. The harmonies are ethereal and otherworldly; the title is the name of a Greek god, who was especially associated with sleep and dreams. The score is published by Oxford University Press.