In an effort to find a way to optimize the learning condition, this study examined the effects of two types of input frequency distribution, skewed-first distribution (SFD) versus balanced distribution (BD), and two types of focus-on-form techniques, input processing (IP) versus input enhancement (IE), on the learning of English participles by Korean middle school students. A total of 91 students participated in this study, divided into five subgroups: SFD + IP, SFD + IE, BD + IP, BD + IE, and Control. The learning outcomes and the generalizability of the learned knowledge were measured through scaled judgment tasks and picture description tasks, immediately after treatment as well as one week later. The results showed that the input frequency distribution factor did not have statistically significant effects on learning and generalizability, while the degrees of explicitness of focus-on-form techniques had statistically significant effects on both. The interaction effects of the two main factors were not statistically significant. More detailed findings are presented with some pedagogical implications for Korean EFL classrooms.