The purpose of this study was to investigate the music teaching efficacy beliefs and commitment to teaching of preservice music teachers enrolled in an introductory music education course. Also explored was the impact of introductory music education course experiences on preservice music teachers' music teaching efficacy beliefs and commitment to teaching. This study was conducted in a sequential explanatory mixed-methods design, organized into two strands (Strand I: Quantitative, Strand II: Qualitative). Introductory music education students (N = 684) from 41 National Association of Schools of Music-accredited institutions participated in Strand I, with a nested sample of 24 interviewees participating in Strand II. Preservice music teachers' efficacy beliefs were interpreted as having two dimensions: music teaching efficacy beliefs and classroom management efficacy beliefs. Mixed-methods analyses indicated that introductory music education students' music teaching efficacy beliefs may have been impacted by a variety of course experiences, including individual mentoring, peer teaching, and field experience. Participants' commitment to teaching may have been strengthened by mentoring, although instances of weakened commitment were rare. Additional findings included the types and qualities of experiences perceived by participants as influential to music teaching efficacy beliefs or commitment.