This paper investigates the structure of German sixth-grade students' interest in science (N = 474; age 11-12 years) by considering different subject-related contexts (biology, chemistry, and physics) and different activities. Confirmatory factor analysis models were designed to validate the hypothetical structure of interest, connecting the whole spectrum of early school science with Holland's RIASEC model, and revealed that students' interest in science is best described by a cross-classified model with latent context and activity factors. Students were most interested in investigative and hands-on activities in all contexts. Despite the young age group, there were significant gender differences with regard to interest in contexts and interest in activities. For example, girls were more interested in "artistic" and "realistic" activities among most contexts and generally in the biological context. Surprisingly, boys were more interested in "social" physics activities than girls. This paper discusses implications for future research, for school science curricula as well as for how to engage students in science with particular emphasis on gender differences.