Outreach science labs aim to promote students' interest. Previous research has often suggested that performing experiments in such labs has a positive effect on their interest. However, these studies often lack a comparison to the effects of performing them at school. This research gap was addressed in the present study. The sample consisted of 402 upper-secondary level students (age: M = 16.53 years, SD = 0.80 years) who performed three experiments on the topic of enzymology either in an outreach science lab (n = 203) or at school (n = 199). Contrary to the assumption, experimentation at the outreach science lab did not outperform experimentation at school in terms of students' psychological state of interest in the comparison to the school setting. Surprisingly, differences in the value-related component of the psychological state of interest were even found in favor of the school treatment.