Males are more likely than females to aspire to and enter scientific careers, a pattern that might be attributed to gender differences in the appeal of school science. Differences might arise, in part, from gender-related interactions with the interest value of school science experiments. If modifiable, the interest value of experiments could influence attitudes toward science and subsequent choices concerning science involvement. In this study, middle school students carried out versions of science experiments designed to vary in their interest value. Experiment modifications, guided by a three-component model of interest, ranged from introduction of fantasy scenarios to manipulation of the difficulty and social context of the experiments. Subjects were 101 middle school students, 46 males and 55 females. Of primary interest were MANOVA comparisons of self-reported interest in the experiments, by gender and experimental condition. In general, interest enhancements were more effective for girls than boys. Boys were more attentive to aspects of the experiments that elicit perceptions of control, whereas girls were more attentive to social aspects.