This study extends an eight-country mapping exercise (McPherson & O'Neill, 2010; see "Research Studies in Music Education" issues 2010-2011) to include students' motivation to study music within the Australian context. It sought to determine whether music learners (students learning an instrument or voice), might be more motivated to study academic subjects at school, and whether gender and socio-economic status (SES) affected student motivation to learn music at school. A total of 2,727 students from grades 5 to 12 completed a questionnaire based on Eccles and Wigfield's expectancy-value framework. Data collected included: ratings of competence beliefs, interest, importance, usefulness and difficulty for music, English, maths, and science; indications of whether the students were currently learning a musical instrument or voice (music learners); and whether they would like to if given the opportunity. There was an overall significant decline in competence beliefs, interest, importance, and usefulness across the school years, in contrast with increased task difficulty ratings across the school years. Music learners reported significantly higher competence beliefs, interest, importance, usefulness, and less task difficulty than non-music learners. This advantage applied across all school grades for music, competence beliefs for English in upper primary and lower secondary school grades, and for maths in lower secondary grades. Although females reported music as more important and useful than males, their competence beliefs and task difficulty ratings were equivalent. Music was considered slightly less interesting for females than for males. The value of music as a subject declined significantly for upper SES students from upper primary to lower secondary schools. The greatest number of participants (40.8%) who expressed a desire to learn a musical instrument came from the lower SES category in upper primary school. This is an important result in the Australian context, indicating that this may be a positive time to recruit learners. This study provides new information regarding the relationship between motivation and desire to learn a musical instrument across school grades, gender, and socio-economic factors.