The paper explores how various teaching methods, namely Phonology-Based Instruction (PBI) and Translation-Based Instruction (TBI), have an effect on students' acquisition of formulaic sequences. 20 multiword expressions were taught to 48 Vietnamese EFL students from three intact classes as 2 treatment groups (PBI and TBI) and 1 control group. Right after completing the tasks, the three groups were tested on their ability to identify (Form Recognition) and produce (Form and Meaning Recall) the lexical phrases by an immediate post-test. A delayed test was administered two weeks later for better comparison of their retention. The results showed that PBI and TBI groups significantly outperformed the control one on most of the test levels. Especially, TBI tended to be more effective than PBI in two cases as regards both Repeating and Non-repeating items. It is believed that if the results and the proposed suggestions of this research are taken into consideration, major improvements could occur in language teaching programs, leading to students' higher vocabulary uptake.