Objective: To determine the efficacy of a high school biology curriculum focused on promoting nutrition literacy skills. Design: High school students participated in a six-week biology curriculum focused on the three subdomains of nutrition literacy: functional use of factual knowledge (FNL); interactive skills in seeking out information (INL); critical interpretation and analysis (CNL). We used a mixed-methods, change-over-time model that leverages longitudinal aspects of instructor practice and students' development. Pre- and posttest measures of FNL, INL and CNL were administered. Students were also given a retrospective pre-post online survey to measure interactive nutrition literacy and self-efficacy towards learning about nutrition topics. Participants: A total of 111 high school 11th and 12th grade students from four sections of a Biology II course participated. Results: Students' overall NL scores improved (P<0.0001) and they also showed gains in each subdomain (FNL, INL and CNL, P<0.0001). Self-efficacy toward learning about nutrition also increased (P<0.0001). Students reported increased communication about the topics with family and peers who were neither classmates or friends (P<0.0001). Conclusions: Participation improved nutrition literacy in each of the subdomains, as well as self-efficacy. Self-efficacy was strongly related to increased communication.