Task-basedlanguage teaching (TBLT) has increasingly been used in an Asian context. However, research into its implementation in Vietnam remains scarce. This study aims to investigate the effects of atask-based intervention on learners’ performance of listening, reading, speaking and writing tasks compared to the effects of a more traditional teaching method (TTM), which is based onform-focusedinstruction in combination with thePresentation-Practice-Productionmethod. Through apretest-posttest design, the researcher can measure the effects of the two settings on learners’ progress. The results show that the participants in the TBLT setting outperformed the participants in the TTM setting for speaking, listening and writing, but not for reading. The results of this study will encourage more research in the field of TBLT implementation in Vietnam.