Objectives <p>Mindfulness is a promising health intervention, showing potential benefits for cognitive functions, particularly memory. Despite evidence suggesting mindfulness improves working memory, inconsistencies in results and methodologies prevent definitive conclusions. This meta-analysis examines the effects of mindfulness interventions on working memory across clinical and healthy populations and various age groups.</p> Method <p>A systematic search for relevant English and Persian articles was conducted across WOS, Scopus, PsycINFO, PubMed, and ISC databases for articles published up to July 2025. Included studies consisted of randomized controlled trials (RCTs), controlled trials (CTs), and single-group studies. Overall, 43 studies with 2776 participants aged 3–85&#xa0;years were analyzed.</p> Results <p>Mindfulness interventions demonstrated a medium effect size on working memory: RCT two-group studies (Hedges’<i> g</i> = 0.55, <i>p</i> &lt; 0.01), CT two-group studies (Hedges’<i> g</i> = 0.40, <i>p</i> &lt; 0.01), and single-group studies (Hedges’<i> g</i> = 0.37, <i>p</i> &lt; 0.01). The effects of mindfulness on working memory (WM) were moderated by the average age of participants within each study and the total duration of mindfulness interventions (in weeks).</p> Conclusions <p>Mindfulness interventions appear to positively affect working memory, with stronger effects related to studies that included younger participants and interventions delivered over a longer number of weeks. However, further primary research, particularly rigorous RCTs, is needed to better understand their impacts on clinical versus healthy populations and across diverse age groups.</p> Preregistration <p>This study was not preregistered.</p>