Gut microbiota impacts host health by mediating beneficial physiological processes. However, growing evidence supports the potential role of microbiota in disease development and progression. In this review, we report current knowledge on pathophysiologic processes mediated by gut microbiota that may be implicated in atherosclerosis development and progression. We also summarize findings provided by clinical studies that indicate an association between gut microbiota composition and/or function and atherosclerotic cardiovascular diseases. Finally, we discuss potential strategies to impact gut microbiota composition and/or function in order to reduce the atherosclerotic cardiovascular risk.