Defensive responses to threatening health messages undermine the effectiveness of health communication. Brief mindfulness meditation training seems to be an effective approach on mitigating defensiveness to health threats and increasing intentions of health behaviors. However, these effects were less explored. The current study therefore aimed to examine the effects of brief mindfulness meditation training on defensiveness to health threats and intentions of health behaviors across two online experiments on sleep health and health screening. Findings of Experiment 1 revealed that brief mindfulness meditation training significantly reduced defensiveness to health message of sleep health, which led to increased intention of healthy sleep behaviors. Findings of Experiment 2 showed that brief mindfulness meditation led to increased intentions of health screening towards a faked rare disease via the serial mediation of increased acceptance of health risk feedback and lowered defensiveness to health message. However, the effect of brief mindfulness meditation training on the health-screening appointment-making behavior was non-significant. These findings provide preliminary empirical evidence demonstrating that brief mindfulness meditation can reduce defensive responses triggered by health threats and increase intentions of healthy sleep behaviors and one-time health screening. Future research should continue to examine the working mechanisms on the effects of brief mindfulness meditation training on defensiveness to health threats, intentions and behaviors in other health domains.