The objectives of the present study were to examine the impact of intensive mindfulness (Vipassana) meditation on psychological wellbeing, and the ways in which this may be mediated by changes in executive function. This was achieved by comparing the performance of people completing their first 10-day Vipassana meditation course with a sample of matched controls, on a number of measures of affect, metacognitive processing, and executive function. The results indicated that mindfulness meditation has significant benefits for psychological wellbeing, which are at least partly mediated by enhanced executive function. However, only partial support was found for the initial hypotheses. The benefits of the meditation course were differentially reflected in significantly reduced depression and negative affect, more moderate reduction in anxiety and rumination, and significantly enhanced executive function. The following is a more detailed exploration of these findings, their relationship to the original hypotheses, and their broader implications.