Background: Teacher self-efficacy for teaching nutrition can positively impact student dietary behaviors; however, limited curricular resources and professional development can serve as barriers to the provision of nutrition education in the classroom. The purpose of this study was to assess the impact of a food-based, integrative science curriculum on fourth-grade teachers' self-efficacy toward teaching nutrition. Methods: Researchers used a quasi-experimental design to implement the FoodMASTER Intermediate (FMI) curriculum in 19 fourth-grade classrooms across Ohio and North Carolina. The Nutrition Teaching Self-Efficacy Scale was used to assess baseline and posttest teacher self-efficacy using a 4-point Likert scale (1 = "not confident at all"; 4 = "very confident"). Analysis of covariance (ANCOVA) and Wilcoxon's signed rank test were used for statistical analysis. Results: Teachers in the intervention group displayed significantly higher post efficacy expectation scores (mean = 3.52; SD = 0.41) than comparison group teachers (mean = 2.86; SD = 0.55). Overall, the intervention group showed significant improvement in self-efficacy on 15 of the 18 items. Discussion: The results suggest providing training and integrative resources to teachers can significantly improve self-efficacy toward teaching nutrition. Future research should focus on determining the amount of training needed to improve the quality of teacher-delivered nutrition education. Translation to Health Education Practice: Health Educators can use the findings to inform the development of teacher trainings in nutrition and health.