To attain characteristic flavor and body attributes, many cheese varieties must be ripened at low temperature for months or even years. Because flavorful cheese has premium value as a food or food ingredient, there is considerable industrial interest in technologies to accelerate the ripening process. Research has shown that the lactic acid bacteria (LAB) present in the cheese matrix have a central role in flavor development, so effective strategies to accelerate or intensify cheese flavor can be derived from a more fundamental understanding of LAB physiology in milk and cheese environments. Although many details must still be elucidated, current knowledge indicates LAB influence cheese flavor development via several key mechanisms including proteolysis, amino acid metabolism, lipase/esterase activity and citrate utilization. This paper provides an overview of these reactions and addresses recent genomic-based advancements that are driving current research to understand how LAB influence cheese flavor development.