<p>Theories of rumination posit that the relationships between trait rumination and depression are reciprocal. Nevertheless, the consistency of such relationships across populations from various countries remains unexamined. The present study aimed to investigate whether the hypothesized reciprocal relationships between trait rumination and depression are consistent across Eastern and Western countries. Employing a prospective two-wave panel design spanning three months, longitudinal data were collected from residents in the United Kingdom (UK) and Japan (Total <i>N</i> = 656). Multi-group cross-lagged path analyses were employed to investigate the relationships between rumination and depression. Overall, we found limited differences in the relationships between trait rumination variables and depression across the UK and Japan. The relationships between rumination and depression, as well as between brooding and depression, were reciprocal, and the magnitude of these associations did not statistically differ between the two country samples. The findings are discussed in the context of theoretical and clinical implications.</p>