Cardiovascular diseases (CVDs), such as atherosclerotic cardiovascular diseases, heart failure (HF), and acute coronary syndrome, represent a significant threat to global health and impose considerable socioeconomic burdens. The intricate pathogenesis of CVD involves various regulatory mechanisms, among which microRNAs (miRNAs) have emerged as critical posttranscriptional regulators. In particular, miR-155 has demonstrated differential expression patterns across a spectrum of CVD and is implicated in the etiology and progression of arterial disorders. This systematic review synthesizes current evidence on the multifaceted roles of miR-155 in the modulation of genes and pathological processes associated with CVD. We delineate the potential of miR-155 as a diagnostic biomarker and therapeutic target, highlighting its significant regulatory influence on conditions such as atherosclerosis, aneurysm, hypertension, HF, myocardial hypertrophy, and oxidative stress. Our analysis underscores the transformative potential of miR-155 as a target for intervention in cardiovascular medicine, warranting further investigation into its clinical applicability.