The study explores the music development, achievement and aspirations of adolescent students who participate in pre-tertiary specialised music programs. A theoretical model is developed for the study to investigate the role and influence of such training in the development of music skills, and explores relationships amongst music experience, music engagement, academic achievement, interpersonal and intrapersonal relationships, personal learning styles, and affective response to music. The data source for the study was the Young Conservatorium program (YCP) at Griffith University. Three sub-studies formed the investigation, two focussing on music development, and one, the program. The first sub-study involved 117 enrolled students, the second, 44 teachers and 112 former students, and the third, 15 case studies. Quantitative and qualitative data were obtained using surveys, tasks, tests, interviews, discussions, reflective journals, and practice logs. A large body of literature has identified a continued need for research that traces the music development of young musicians in adolescence, research that utilises both large and small sampling (particularly case studies), and is conducted at the time of training. The present study was conducted over two years, utilised a larger population than many previous studies, involved case studies, and combined contemporaneous and retrospective approaches. Research findings contribute to knowledge regarding young musicians' music training and learning in pre-tertiary specialised music programs, and the nature of pre-tertiary specialised music programs themselves: their rationale, methods of instruction, and overall effectiveness. They highlight the types of music programs and music training provisions available to young Australian musicians, and, though showing students to frequently engage in multiple music learning environments, confirm the need for individuals demonstrating above-average music ability to access specialised music tuition and opportunities, develop in a supportive learning environment, and interact with students of similar interests and abilities. Although also suggesting there to be a number of factors associated with pre-tertiary specialised music training that can deter some students, such factors tend to be non-musical in nature. In all, the study does show a trend for the families of young, above-average musicians to choose to provide for their children access to pre-tertiary specialised training, and for participants to gain from this experience. The study seeks to enhance understanding of the conditions though which music development is nurtured; it confirms the importance of exposure and opportunity, the collective efforts of the family and community, and the need for hard work and perseverance to usually be exercised by young musicians themselves. Common trends associated with the music development of young, above-average musicians pertained to music training and influences, characteristics, goals, and achievement. Early music exposure, guidance, and positive music experiences were found to be conducive to music learning. The establishment of a practice routine, increasing engagement with music, the formation of broad music preferences, demonstration of high music aptitude, musical and academic achievement, and goal-setting all characterised the experiences and marked the qualities of students sustaining their music interests in adolescence. Interpersonal support and developing intrapersonal attributes, personal learning styles and increasing affective response to music, together with developing cognitive and metacognitive skills, were generally shown to typify the music development of young, above-average musicians in adolescence.