Matrix metalloproteinases (MMPs) belong to a unique family of enzymes studied because of their vital role within and outside the central nervous system. By regulating signaling processes and shaping extracellular matrices (ECM), these proteases provide required conditions for many processes both of physiological and pathological nature. Due to their immense destructive power, MMPs require very tight regulation and are only expressed at low levels in healthy individuals, if at all. Regulation is achieved on many levels and is mediated by specific metalloproteinase inhibitors, known as tissue inhibitors of metalloproteinases (TIMPs). Many other factors, molecules, and interactions also play essential roles. To understand the intricate workings of MMPs, we need to understand the ECM, the molecules, the proteins, and the cells that create it. Besides their functions during development, these enzymes have been detected in many pathological conditions. Research has made advances in demonstrating their molecular mechanisms. However, much is still unknown owing to their complexity. Future results will be able to guide specific treatment protocols to cure many diseases in their early phases to prevent future fatal outcomes.