Despite more interest in mindfulness meditation practice among stock investors, to date there is no empirical evidence to support the benefits of this meditation practice. This research aims to provide groundbreaking evidence. Data were collected from 145 individual stock traders and 81 professional stock traders in Thailand (total N=226). Results from partial least squares structural equation modeling indicates that respondents who practiced mindfulness meditation more intensively reported better trading performance than individuals who did not and those who meditated less intensively. In particular, meditation practice is found to be associated with higher trading discipline, which in turn, associated negatively with the frequency of panic selling and overreaction to news; together, these factors strongly relate to trading performance.