This study examined whether simultaneously observing and making gestures while studying animations would lighten cognitive load and facilitate the acquisition of grammatical rules. In contrast to our hypothesis, results showed that children in the gesturing condition performed worse on the posttest than children in the non-gesturing, control condition. A more detailed analysis of the data revealed an expertise reversal effect, indicating that this negative effect on posttest performance materialized for children with lower levels of general language skills, but not for children with higher levels of general language skills. The finding that for children with lower language ability, cognitive load did not decrease as they saw more animations provided additional support for this expertise reversal effect. These findings suggest that the combination of observing and making gestures may have imposed extraneous cognitive load on the lower ability children, which they could not accommodate together with the relatively high intrinsic load imposed by the learning task.