Teaching EFL writing has been one of the most trending research fields recently. Among the techniques being tested, using instructional rubrics has drawn much attention from researchers and teachers. This study aimed to investigate the effectiveness of using rubrics in enhancing students’ writing skill and the students’ attitudes towards this technique. The study used the experimental research design. The participants were thirty English-majored eleventh-grade students (N=30) in a high school in Can Tho City, Viet Nam. The main research tools included two guiding rubrics, one writing pre-test, two writing post-tests, and a questionnaire. Holistic and analytic rubrics were used in the teaching of writing skill to the participants to help them understand the targets for learning and the standards of quality for their writing work.  Data from the pre- and post- writing tests indicated significant changes in students’ writing performance after using both holistic and analytic rubrics. Besides, the results of the questionnaire revealed learners’ positive perceptions of this technique. It could be suggested that high school teachers should take into account the use of rubrics in teaching writing for EFL students.