Can teachers' inflated praise make children from low socioeconomic status (SES) backgrounds seem less smart? We conducted two preregistered experiments to address this question. We used hypothetical scenarios to ensure experimental control. An experiment with primary school teachers (N = 106, ages 21-63) showed that when a child from a low-SES (vs. high-SES) background succeeded in school, teachers attributed this success more to hard work and delivered more inflated praise (e.g., "You did incredibly well!") but less modest praise (e.g., "You did well!"). An experiment with primary school children (N = 63, ages 10-13) showed that when children learned that another child received inflated praise (while an equally performing classmate received modest praise or no praise), they perceived this child as less smart but more hardworking. These studies provide converging evidence that teachers' inflated praise, although well-intentioned, can make children from low-SES backgrounds seem less smart, thereby reinforcing negative stereotypes about these children's academic abilities.