Recent studies have shown that the metacognitive judgments adults infer from their experiences of encoding effort vary in accordance with their naive theories of intelligence. To determine whether this finding extends to elementary schoolchildren, a study was conducted in which 27 third graders (M[subscript age] = 8.27) and 24 fifth graders (M[subscript age] = 10.39) read texts presented in easy-or difficult-to-encode fonts. The more children in both grades viewed intelligence as fixed, the less likely they were to interpret effortful or difficult encoding as a sign of increasing mastery and the more likely they were to report lower levels of comprehension as their perceived effort increased. This suggests that children may use naive theories of intelligence to make motivationally relevant inferences earlier than previously thought.