Considerable research has focused on how best to satisfy modern societies’ needs for skilled labour in the field of science. The present study evaluated an intervention programme designed to increase secondary school students’ motivation to pursue a science career. Students from 3 schools of the highest educational track participated for up to 2 years in the intervention programme, which was implemented as an elective in the school curriculum. Our longitudinal study design for evaluating the effectiveness of the intervention programme included all students at the grade levels involved in the programme with students who did not participate serving as a control group. Mixed-model analyses of variance showed none of the intended effects of the intervention programme on science motivation; latent growth models corroborated these results. When the programme began, students who enrolled in the science elective (n = 92) were already substantially more motivated than their classmates (n = 228). Offering such an intervention programme as an elective did not further increase the participating students’ science motivation. It seems worthwhile to carry out intervention programmes with talented students who show (comparatively) little interest in science at the outset rather than with highly motivated students who self-select into the programme.