<p>The human microbiome may play a significant role in both health and disease. However, most studies to date have focused on the microbiome’s role in pathogenesis, while its potential role in promoting well-being remains underexplored. We conducted the first meta-analysis synthesizing empirical evidence on associations between the human microbiome and psychological well-being. Based on eight analyzed studies (<i>N</i> = 2526 participants), we found that both microbial diversity and taxonomic abundance were positively associated with psychological well-being, with diversity emerging as the stronger predictor. Notably, these associations appeared consistent across sex and age. This study provides preliminary evidence that microbiome composition may support salutogenic processes and offers a foundation for future integration of microbiome science into psychological and clinical interventions. However, given the small number of empirical studies included in the meta-analysis, the generalizability of these findings remains limited. Further research is required to strengthen and refine our understanding of the microbiome-well-being relationship.</p>