This study explores gender dynamics in teacher-student interactions during a route planning task in science classes, examining six classes—three in Year 5 (ages 8-9) and three in Year 6 (ages 10-11) —in an English-medium international school in the Netherlands. According to the literature, these specific years mark a notable shift in children’s gender identity development, such as in relation to male-dominated fields. Our findings indicate a corresponding shift in teacher-student dynamics, with teachers exhibiting prioritised interaction with boys in Year 6 but not 5. The most pronounced difference surfaces in the form of positive feedback, with girls receiving substantially less reinforcement in Year 6. Importantly, these altered teacher-student interactions do not align with gender differences in spatial abilities as measured by relevant spatial tests. However, girls in Year 6 participated less and assumed leadership roles in the activity less frequently. This suggests a potential impact of internalised gender stereotypes on girls' assertiveness and engagement in the classroom, which teacher-student interactions might reinforce. Our findings highlight the complex interplay of gender biases, teacher-student interactions, student engagement, and performance on spatial tasks, offering implications for educators aiming to cultivate equitable and inclusive learning environments.