After noting the near-universal presence of rhythmic response in play in all cultures, this paper looks first at the historical development of theories of play, and then examines current theories of play and their implications in the teaching of music to young children. The first section reviews 19th and early 20th century theories of play, including Schiller's surplus energy theory, Hall's recapitulation theory, Groos's instinct-practice theory, Patrick's relaxation theory, and Froebel's insights into children's play and its importance in psychological and educational development. The next section provides an overview of more recent theories of play, including Parten's model of levels of social play and Freud's and Erikson's psychoanalytic theory of play. The paper pays particular attention to the role of play in Piaget's cognitive-development theory and Piaget's stages of play development from practice play to symbolic play to games with rules. The final theorist discussed is Sutton-Smith, who proposed the existence of rational and irrational play. The next section discusses the difficulty in integrating the many differing views of play and reviews Frost's efforts in this area. The final section focuses on early childhood music education, particularly Orff Schulwerk, in which play is used as a primary tool for learning. Singing games and the use of play in learning to play instruments are discussed. Finally, Stanwick's attempts to apply play theory to music education are described, highlighting his views of mastery, imitation, and imaginative play. (AC)