The purpose of this grounded theory research was to investigate music teachers' perceptions of the role and influence of performances in K-12 music programs and the processes by which these performances impact music teaching and learning. Three specific research questions informed this study: (1) What role do performances play in school music programs? (2) How are music teachers' pedagogical decisions informed or influenced by their efforts to mount performances? and (3) What other aspects of the music teaching-learning process are influenced by efforts to mount performances, and what form does this influence take? Five themes emerged to describe the ways in which efforts to prepare and mount performances interact with the music teaching and learning process: community expectations, student motivation, time management, teaching strategies, and teacher views of performance. These themes were used to generate an emergent theory including two interlocking process cycles that illustrate the ways in which performances are situated within school music programs. Implications for the field of music education and for future research are discussed.