The gut microbiota plays a crucial role in regulating host amino acid availability and metabolism through complex interactions with the host metabolic processes. This review summarizes three main mechanisms through which the microbiota influences host amino acid homeostasis. Firstly, gut microbiota actively competes for luminal amino acids derived from the diet and concurrently contributes to the host's amino acid pool through biosynthesis. Secondly, they modulate host intestinal hydrolases and amino acid transporters, thereby fine-tuning amino acid absorption and systemic bioavailability. Thirdly, microbially secreted factors, including diverse metabolites and extracellular vesicles, reprogram host amino acid metabolic pathways. The inherent inter-individual variations in microbial composition and metabolic capacity highlight the necessity of personalized therapeutic strategies targeting the microbiota. By summarizing current findings, this review aims to provide a deeper understanding of this dynamic interplay and to identify promising avenues for future investigations in the field.