MicroRNAs (miRNAs) are small, noncoding RNAs that are essential for regulating gene expression at the posttranscriptional stage. Recent research shows that miRNAs are crucial in the development of two major global health issues: obesity and cancer, two significant health issues worldwide. This study examines the complex mechanisms by which miRNAs govern vital biological processes, including adipogenesis, cancer, and metabolic dysregulation. We highlight the dual function of miRNAs as oncogenes and tumor suppressors in obesity-related malignancies and investigate their potential as prognostic and diagnostic markers. To demonstrate their varied roles, specific examples of vital miRNAs are underscored, such as miR-21, which promotes adipogenesis and is overexpressed in various cancers, and miR-34a, a tumor suppressor involved in cell cycle arrest and apoptosis. In addition, we examined the recent developments in miRNA-based therapies, which include miRNA inhibitors, mimics, and novel delivery vehicles and have the potential for treating obesity-related malignancies. This review aims to clarify, within the framework of miRNA biology, the therapeutic potential of miRNAs in addressing the interrelation between obesity and cancer.