The integration of mindfulness practice within online training programs has gained traction due to its potential to enhance learning effectiveness. This study investigates the impact of a 9-min online mindfulness exercise on mitigating distractions during online learning and their influence on training effectiveness. Two empirical studies (n study 1 = 93, n study 2 = 116) were conducted within the context of a large real estate company’s online training program. Two experiments randomly assigned employees to one of the two conditions: experimental condition (9-min mindfulness intervention) or active control condition (mindfulness explanation). Study 1 suggested that participants engaging in a mindfulness intervention achieved higher training effectiveness (measured by a 10-item quiz) compared to a control group. Building on these results, Study 2 explored the mediating roles of attention (tested by the Attention Network Test) and motivation to learn (assessed by a standardized scale).