This research aimed to find out whether there was a correlation between grammatical knowledge and writing ability of the second year students of MAN 1 Kuantan Singingi. The population was the second year students of MAN 1 Kuantan Singingi. The sample was decided by using cluster random sampling and there were XI MIA 2 and XI MIA 3 as the samples. Grammar test was applied to know the students’…