Researchers have reported that participation in agricultural education reinforces STEM concepts, often through project-based learning. The use of projects is common in agricultural education. However, the instructional importance of certain elements of these projects is not well understood. We conducted a quasi-experimental study to examine the effect of project authenticity on learning. Agriculture students in Texas were sampled and assigned as a cohort to one of four treatment groups (N = 219). Fourteen cohort groups (class periods) were identified across five sites. Each cohort was randomly assigned to one of four project types to learn about electricity. The four project types varied in their degree of project authenticity. Analysis of covariance (ANCOVA) was used to test the effects of project authenticity on change scores in a pretest-posttest quasi-experimental design. Learning varied on authenticity. A test of project type groups yielded statistically significant results (p < 0.025) with small effect size ([omega]2 = 0.04). Pairwise comparisons revealed no differences between the most and least authentic projects but did reveal statistically significant differences between the two projects with medium levels of authenticity, and the other two (i.e., least authentic and most authentic). The relationship between learning and authenticity was not linear. We recommend that teachers and curriculum designers deliberately consider the importance of authenticity when designing project-based learning opportunities for students.