OBJECTIVES: There is growing evidence that mindfulness has positive consequences for both psychological and physical health in both clinical and non-clinical populations. The potential benefits of mindfulness underpin a range of therapeutic intervention approaches designed to increase mindfulness in both clinical and community contexts. Self-guided mindfulness-based interventions may be a way to increase access to the benefits of mindfulness. This study explored whether a brief, online, mindfulness-based intervention can increase mindfulness and reduce perceived stress and anxiety/depression symptoms within a student population. METHOD: One hundred and four students were randomly allocated to either immediately start a two-week, self-guided, online, mindfulness-based intervention or a wait-list control. Measures of mindfulness, perceived stress and anxiety/depression were administered before and after the intervention period. RESULTS: Intention to treat analysis identified significant group by time interactions for mindfulness skills, perceived stress and anxiety/depression symptoms. Participation in the intervention was associated with significant improvements in all measured domains, where no significant changes on these measures were found for the control group. CONCLUSIONS: This provides evidence in support of the feasibility and effectiveness of shorter self-guided mindfulness-based interventions. The limitations and implications of this study for clinical practice are discussed.