This paper aims to survey the studies on middle Korean grammar done so far and to suggest the new directions for better studies. For almost 100 years we have studied middle Korean grammar with fervor. Thanks to this we could understand a lot of things about middle Korean grammar and also find interesting issues to debate. Some issues, mainly on several (pre)final endings(-□-, -오-, -으시-, -잇가/-잇고) of middle Korean, evoked heated arguments among researchers. Although all of them not introduced, a number of brilliant studies brought us to wonderful understanding of the secret properties in middle Korean. For the future studies on middle Korean grammar I suggest the three directions as follows: the studies of middle Korean grammar in view of ⅰ) a base of phonology, ⅱ) diachronic information, and ⅲ) linguistic typology. I hope that young and devoted researchers will continue to study middle Korean grammar enthusiastically as we have done so far.