Self-regulated reading-to-write (R2W) can be portrayed as learners' proactive learning of useful elements (e.g. content, rhetorical features, and conventions) from reading by using strategies, which is an effective mechanism connecting reading and writing, to improve their writing competence. In the present study, six major types of self-regulated R2W strategies, i.e. mining reading, writerly reading, cognitive strategies, purposive reading, recalling while writing, and peer revision reading that can contribute to writing competence were included in the proposed self-regulated R2W framework. Importantly, a self-regulated R2W scale was established to understand the impacts of four types of strategies. Participants were 458 primary students (9 to 13 years old, M = 10.12, SD = 0.62) in Hong Kong. They completed the self-regulated R2W questionnaire along with motivational variables and a writing competence test. The motivational variables (i.e. self-efficacy and perceived task values) were positively related to self-regulated R2W strategy use. Important differences in self-regulated R2W strategy use among the high, average, and low achievers were identified. Results indicated that self-regulated R2W strategy use had positive impacts on writing competence. This is the first time that reading-to-write is proposed from a self-regulated learning perspective in ESL/EFL school contexts. The self-regulated R2W framework, scale and positive impacts of strategy use on writing have important implications for future research and practices. Copyright © 2023 SAGE Publications.