The two purposes of this study were to: (a) define music teacher identity and its underlying constructs based on a critical examination of the extant research, and (b) develop an instrument to measure selected constructs from among a sample of music teachers across years of teaching The Music Teacher Identity Scale (MTIS), a researcher-constructed data gathering instrument, was developed to measure two constructs of music teacher identity: Music Teacher Self-Efficacy and Music Teacher Commitment. Participants in the study were selected using a stratified sampling technique, based on music teaching level, and MENC Division membership, producing a total of 2,500 possible participants.

Descriptive statistics, Cronbach's coefficient alpha, item-total corrected correlation, and inter-item correlation were used to evaluate the degree of reliability of the survey instrument. A factor analysis was calculated to provide evidence of the construct validity for the measurement instrument. Factorial Analysis of Variance was used to find differences among the constructs of Music Teacher Efficacy and Music Teacher Commitment by year of teaching, gender, school location, teaching area, and by teaching level. The MTIS had an overall reliability of α = .81, with the individual constructs of Music Teacher Self-Efficacy reliability of α = .87, and Music Teacher Commitment of α = .67. The two constructs were found to contribute 42.17 percent of the variance through the exploratory factor analysis. Statistically significant differences were found among all years of teaching experience for Music Teacher Self-Efficacy. Statistically significant differences were found between Music Teacher Self-Efficacy and Music Teacher Commitment at each experience level examined. Music Teacher Commitment was found to be a statistically significant different between men and women. A significant three way interaction effect was found in Music Teacher Commitment at the 6–10 years of teaching experience between Middle/Junior High School and High School, and again at the 31+ years of teaching experience between Middle/Junior High School and High School. Recommendations were suggested for future research regarding music teacher identity construction.