This chapter presents a theory-driven typology based on MLR Theory, focusing on its predictions regarding phonological systems that involve vowel reduction. At the heart of MLR Theory is mora loss, where vowels lose their moras, which may be followed by processes such as feature loss and mora restoration. These mechanisms together give rise to systems of vowel reduction, and the chapter aims to identify which reduction patterns, as defined by the theory, are observed in languages and which are not. The discussion begins with an exploration of the key concepts of mora loss and mora restoration, followed by an analysis of peripheralization and its role in vowel reduction. Next, the chapter looks at feature loss and its effects on specific vowel groups, then moves on to examine centralization and its impact. The chapter also investigates the reduction of long vowels, the diverse environments in which vowel reduction takes place, and how these processes interact with factors like opacity, morphemes, and vowel harmony.