Genetic essentialism of race is the belief that racial groups have different underlying genetic essences which cause them to differ physically, cognitively, or behaviorally. Apparently, no published studies have explored if belief in genetic essentialism of race among adolescents differs after many weeks of formal instruction about different domains of genetics knowledge. Nor have any studies explored if such differences reflect a coherent change in students' racial beliefs. We use a quasi-experimental design (N = 254 students in 7th-12th grade) to explore these gaps. Over the course of 3 months, we compared students who learned from a curriculum on multifactorial inheritance and genetic ancestry to students who learned from their business as usual (BAU) genetics curriculum that discussed Mendelian and molecular genetics without any reference to race, multifactorial genetics, or genetic ancestry. Relative to the BAU condition, classrooms that learned from the multifactorial genetics and ancestry curriculum grew significantly more in their knowledge of multifactorial genetics and decreased significantly more in their genetic essentialist perceptions, attributions, and beliefs. From a conceptual change perspective, these findings suggest that classrooms using a curriculum emphasizing genetic complexity are more likely to shift toward a coherent anti-essentialist understanding of racial difference.