Whether and when children can apply their developing understanding of belief to persuasion was examined using interactive puppet tasks. Children selected 1 of 2 arguments to persuade a puppet to do something (e.g., pet a dog) after hearing the puppet's belief (e.g., "I think puppies bite"). Across 2 studies, 132 children (ages 3-7 years) engaged in these persuasion tasks and in false-belief reasoning tasks, presented in puppet and story formats. Belief-relevant argument selection increased with age, as did appropriate reasoning about false beliefs, and occurred more in puppet than story tasks. Results suggest that improvements in belief reasoning in early childhood may be reflected in social interactions such as persuasion.