Mindfulness-Based Cognitive Therapy (MBCT) and Mindfulness-Based Stress Reduction (MBSR) emphasize the importance of mindfulness practice at home as an integral part of the program. However, the extent to which participants complete their assigned practice is not yet clear, nor is it clear whether this practice is associated with positive outcomes.For this systematic review and meta-analysis, searches were performed using Scopus and PubMed for studies published through to the end of 2015, reporting on formal home practice of mindfulness by MBSR or MBCT participants.Across 43 studies (N = 1427), the pooled estimate for participants' home practice was 64% of the assigned amount, equating to about 30 minutes per day, six days per week [95% CI 60–69%]. There was substantial heterogeneity associated with this estimate. Across 28 studies (N = 898), there was a small but significant association between participants’ self-reported home practice and intervention outcomes (r = 0·26, 95% CI 0·19,–0·34).MBSR and MBCT participants report completing substantial formal mindfulness practice at home over the eight-week intervention, albeit less than assigned amounts. There is a small but significant association between the extent of formal practice and positive intervention outcomes for a wide range of participants.