QUESTION: Alexithymia has been found to be modifiable through treatment, with associated clinical benefits. Recent studies have begun to test the potential of mindfulness-based interventions to reduce alexithymia, using skills-based, group training to improve non-judgemental, present-moment awareness. The objective of this review therefore was to conduct a systematic synthesis to assess the current state of knowledge about the effect of mindfulness-based interventions on alexithymia to inform clinical practice. STUDY SELECTION AND ANALYSIS: We carried out a systematic review of the literature and found four randomised controlled trials of the effect of mindfulness-based interventions on alexithymia, with a combined total of 460 participants. FINDINGS: A random-effects meta-analysis, combining study endpoint data, showed a statistically significant effect of mindfulness-based treatment on alexithymia (Toronto Alexithymia Scale) compared with the control group (mean difference=-5.28, 95% CI -9.28 to -1.28, p=0.010). Subgroup analysis was conducted to investigate sources of heterogeneity (I(2)=52%). Heterogeneity was reduced when the meta-analysis was restricted to interventions of a similar duration (3 months or less). CONCLUSIONS: Findings from our study should be replicated in further research with larger samples; however, the results indicate that mindfulness-based interventions may be an effective treatment in reducing alexithymia.