This paper explores notions of (hetero)sexuality circulating in elementary school classrooms through an analysis of students' own talk and interactions. Data collected during a multi-site ethnography in a diverse set of elementary schools demonstrate that while curricular silences and teachers contribute to heteronormative classroom environments, children also take up and perpetuate heteronormative ideals in their own interactions both through explicitly anti-gay talk and by silencing of lesbian, gay, bisexual, transgender and queer (LGBTQ)-inclusive perspectives, thereby maintaining the heteronormativity of schools. Findings show (hetero)sexuality to be a constitutive part of classroom life, present even in the formal teaching/instructional time of elementary schools and even in the talk/activities of children themselves. Uninterrupted, these discourses intersect with the official curriculum and reify schools as places in which LGBTQ people/perspectives are not welcome or valued, creating social and academic effects for all students.