Students' unrestricted interview responses regarding why they plan to either pursue (or not pursue) maths-related careers are the focus of the present study. Within the Expectancy-Value theory of achievement motivation of Eccles, Wigfield and colleagues, success expectancy beliefs and values are posited to be the main predictors of choices to participate in maths, with indirect influences of task demand, where participation choices are operationalised in terms of high school maths course enrolments. The present study extends consideration of participation choices to maths-related career plans, being a longer-term outcome with clear social relevance. Open-ended qualitative techniques are employed, rather than correlational approaches common within this perspective, to investigate students' reasons for participation in maths-related careers. Findings corroborate influences identified within the Expectancy-Value framework, providing strong support for these factors as sources of students' intentions to pursue (or not pursue) maths-related careers.