This study explored the processes of utilization of resources in secondary students' self-regulated strategic writing for academic studies in an English as medium of instruction context in Hong Kong. Drawing on multiple data sources collected through the observation of lessons, stimulated recall and semi-structured interviews, the study examined the features of six secondary students' self-regulated writing with focus on how they used resources strategically to overcome challenges in academic writing. In the analysis, we compared self-regulated strategic writing processes of high achievers and underachievers. Differences were found in the ways resource utilization unfolded in the learners' self-regulated writing activities. Seven processes, namely, noticing, selecting, reorganizing, evaluating understanding, reviewing and memorizing, imitating, as well as adapting, were found in the high achievers' self-regulated writing, while only imitating and reorganizing were identified in the case of underachievers. Differences were also found in terms of why and how the high achievers and the underachievers imitated and reorganized resources. The study suggests that underachievers should be encouraged to reflect on their self-regulated writing processes and language teachers can help these students to deploy strategies in ways high achievers use them. We draw on sociocultural theory in our discussion.