Theoretical accounts and preliminary evidence suggest that Mindfulness-Based Interventions (MBIs) improve cognitive function, but reviews of empirical studies have provided mixed results. To clarify empirical evidence, we conducted a meta-analysis of 25 studies (n = 1439) and examined the effects of MBIs on four cognitive domains: attention, working memory, long-term memory, and executive function. The summary effect sizes indicate that MBIs produce non-significant effects on attention (SMD = 0.07), working memory (SMD = 0.16), and long-term memory (SMD = -0.12), while a small effect was observed for executive function (SMD = 0.29). Given significant heterogeneity across studies, we conducted meta-regression analyses with sample characteristics, age, number of treatment sessions, treatment duration, intervention type, control group type, and study design. We found moderating effects of intervention type on attention and executive function. Although the current study highlights preliminary evidence for improvements in executive function, overall results suggest non-significant findings for attention, working memory, and long-term memory. To draw a firm conclusion, further research is needed to address methodological challenges in meta-analysis and the limitations of existing studies.