Chinese and Canadian children were compared to examine cultural and developmental differences in lay theories of change: implicit beliefs about how the world develops and changes over time. Chinese and Canadian children (ages 7, 9, and 11 years) made predictions about future performance, relationships, happiness, and parental incomes based on a series of scenarios. Overall, the Chinese children predicted greater change than did the Canadian children, indicating that they believed more in change than did the Canadians. Moreover, cultural differences increased significantly with age: In comparison with their Canadian counterparts, Chinese children made no more change predictions at age 7, made slightly more change predictions at age 9, and made significantly more change predictions at age 11. This was true for questions starting with an extremely positive or negative state and those starting with a neutral state. Reasons for cultural and developmental differences were discussed.