Perceived post-traumatic growth (PTG) refers to self-reported positive change resulting from the struggle with a traumatic experience. There is evidence that mindfulness- and acceptance- based interventions (MABIs) can increase perceived PTG, but this has yet to be reviewed or assessed using meta-analysis. This study investigated the effectiveness of MABIs at increasing perceived PTG across the five domains of the Posttraumatic Growth Inventory. Systematic searches of bibliographic databases and the grey literature (2026, January 18) led to the selection of nine randomised controlled trials (total n = 1114), all conducted with cancer patients. Risk of bias was “high” for three studies and presented “some concerns” for six studies. Meta-analyses (total n = 976), performed using a random-effects model to pool individual study effect sizes (Hedges’ g ), found medium effects on Global PTG ( g = 0.54, 95% CI [0.24 to 0.83]) and New Possibilities ( g = 0.51, 95% CI [0.27 to 0.75]), small effects on Relating to Others ( g = 0.39, 95% CI [0.19, 0.59]) and Personal Strength ( g = 0.38, 95% CI [0.17 to 0.6]), and negligible effects on Spiritual Change ( g = 0.14, 95% CI [0.03 to 0.27]) and Appreciation of Life ( g = 0.24, 95% CI [0.035 to 0.44]). These findings suggest possible effects, but confidence was limited by the small number of studies, risk of bias, intervention heterogeneity, and lack of generalisability beyond oncology populations. There is a need for better designed randomised controlled trials among diverse trauma-affected populations to develop a more robust evidence base.