ABSTRACT In an effort to meet students' arts education needs, the New York City Department of Education (NYCDOE) collaborated with various community organizations to develop the Blueprint for Teaching and Learning in the Arts in 2004. In 2008, the NYCDOE updated the music portion with a publication known as the Blueprint for Teaching and Learning in Music PreK-12. After designing the new "Standards and curriculum guide" with the intention of changing arts education in New York City public schools, the NYCDOE organized various professional development workshops to prepare music teachers. Although the responsibility of music teachers was obvious, the role of assistant principals, who evaluate the performance of music teachers, was not apparent. In this study, I employed questionnaire, interview, observation, and document analysis as data gathering instruments to investigate the implementation and supervision of the music education portion of The Blueprint standards. I used a collective case study approach to conduct the study in the public high schools of New York City in light of the changing conditions of education in the NYCDOE. I found that in the New York City public high schools, not every music educators was familiar with The Blueprint, and the NYCDOE did not make its implementation mandatory to all music educators. Implementation of The Blueprint depended on individual teachers' choice. Because the NYCDOE did not train music supervisors how to supervise and evaluate the implementation of The Blueprint, they did not use the criteria from The Blueprint to evaluate music teachers. Data from classroom observation of music teachers indicated that they were implementing some of The Blueprint's strands. Music educators that were apprehensive about using The Blueprint believed that their established method of teaching music was sufficient, and that the NYCDOE does not always follow through with its policies. Administrative support and resources were not significant barriers except in one case, but time was an obstacle to the implementation of The Blueprint, especially the rehearsal time. Time for other subjects took precedence over music.