The present research aims to examine the longitudinal relationship among intrinsic motivation toward Korean, academic self-efficacy in Korean, Korean teaching activities perceived by students, the time spent on studying Korean, the ability to understand Korean lessons, and Korean academic achievement using latent growth modeling. We used the longitudinal data of Time 1 (2005) to Time 3 (2007) collected by KEDI (Korean Educational Development Institute) since 2005. The results showed that (1) the slope of change in intrinsic motivation and academic self-efficacy decreased during the three year period; (2) as the rate of change in the perceived teaching activities increased, intrinsic motivation and academic self-efficacy also rose; (3) the slope of change in than the initial state of intrinsic motivation had a greater impact on both rates of change in studying time and the ability to understand lessons; and (4) the effect of the initial state of academic self-efficacy on Korean academic achievement at the first grade was positively mediated by the initial state of ability to understand lessons.