Background: Women (along with minority ethnic and low-income communities) remain underrepresented in engineering, despite a 30-year history of research and equality legislation. Compared with the United States and other European Union countries, this underrepresentation is particularly pronounced in the United Kingdom. While existing literature gives insights into factors shaping retention and progression in university engineering students, comparatively less is known about the development of primary and secondary school students' engineering aspirations. Purpose: This paper contrasts science and engineering analyses to explore how relationships between background and attitudinal factors and aspirations change across primary and secondary schools. We examine the relative influence of gender on aspirations in both science and engineering. Design/Method: We drew on survey data from more than 20,000 English students from the ASPIRES projects. A multilevel regression approach is implemented to test for the effects of gender, ethnicity, and cultural capital on science and engineering aspirations. Results: Gender is the main factor related to engineering aspirations, while science aspirations are influenced by a broader range of factors. School-level factors become increasingly important for engineering aspirations. We also report evidence of the early distinctiveness of young women who aspire to engineering in terms of their relatively high self-concept and motivations. Conclusions: The association of engineering with masculinity is evident in aspirations from age 10, and students aspiring to engineering are distinctive in several respects. Efforts aimed at improving participation in engineering might more usefully focus on challenging the elitist culture and practices, which may influence student perceptions, rather than focusing on changing student aspirations directly.