Background: When writing a text, students are required to do several things simultaneously. They have to plan, translate and review, which involve demanding cognitive processes. In order to handle this complexity, writers need to develop a writing strategy. The two most well-defined writing strategies that have been identified, are those of a planning strategy and a revising strategy. Aims: To establish whether students will be more competent in managing the complexity of writing when writing instruction is adapted to their habitual writing strategy, thus resulting in better texts. Sample: 113 high school students (10th grade). Method: Students were randomly assigned to either the planning or the revising condition. To identify writing strategies, students completed a questionnaire concerning their planning and revising tendencies. To measure the level of writing skill, students' texts written during pre-test and post-test were analysed. Results: The effect of instruction based on a planning strategy interacted with the level of planning or revising strategy: the greater the use of such a strategy, the larger the effect on writing skill. In contrast, the effect of instruction based on a revising writing strategy did not interact with the level of planning or revising strategy. Results imply that students with strong tendencies to plan or revise profited from writing instruction based on a planning strategy, while students with a low tendency to plan or revise profited more from instruction based on a revising strategy. Conclusion: Adapting writing instruction to students' level of writing strategy, is an effective approach for learning to write.