This study examined whether dictation or dictogloss is more efficient on improving Korean high school students’ English collocation knowledge. The 60 Korean high school students participated in the study and they were assigned to either the dictation or dictogloss group. The participants’ English collocation knowledge was measured through pre-, immediate post-, and delayed post-tests over the experimental period. The results showed that the students in the dictogloss group displayed better immediate learning outcomes than those in the dictation group, implying the immediate help from the use of dictogloss tasks in acquiring collocations. However, as to the retention of collocations, both of the dictation and dictogloss tasks were effective, showing no sustained initial advantage of dictogloss. Based on the findings of this study, implications and suggestions on how to teach L2 collocation more effectively in instructional settings were made.