Cognitive determinants of emotion regulation, such as effortful control, have been hypothesized to modulate young children's physiological response to emotional stress. It is unknown, however, whether this model of emotion regulation generalizes across Western and non-Western cultures. The current study examined the relation between both behavioral and questionnaire measures of effortful control and densely sampled, stress-induced cortisol trajectories in U.S. and Chinese preschoolers. Participants were 3- to 5- year-old children recruited from the United States (N = 57) and Beijing, China (N = 60). Consistent with our hypothesis, U.S. children showed a significant negative relation between maternal-rated inhibitory control and both cortisol reactivity and recovery. However, this was not replicated in the Chinese sample. Children in China showed a significant positive relation between maternal-rated attentional focusing and cortisol reactivity that was not seen in the U.S. Results suggest that children who reside in Western and non-Western cultures have different predictors of their emotion-related stress response.