Despite　self-regulated　learning　(SRL)　being　considered　to　represent　a　model　of　optimal　learning,　the　effects　of　SRL　strategy-based　instruction　in　L2　writing　remain　relatively　underexplored,　especially　in　the　Chinese　tertiary　setting.　To　fill　such　lacuna,　the　present　study　explored　the　effects　of　an　SRL　strategy-based　writing　intervention　program　on　Chinese　university　English-as-a-foreign-language　(EFL)　learners＇　writing　performance　and　self-regulated　writing　strategy　use.　A　quasi-experimental　design　was　employed　with　97　third-year　English-major　students.　The　experimental　group　(n　=　39)　received　a　12-week　intervention　designed　on　a　framework　conceptualized　according　to　Zimmerman　(2000)　and　Pintrich　(2004).　The　control　group　(n　=　58)　received　a　regular　traditional　writing　course　concurrently.　Data　were　collected　with　a　Questionnaire　for　Self-regulated　Learning　Writing　Strategies　(QSRLWS),　writing　tests,　and　student　interviews.　ANCOVA　results　revealed　a　significant　intervention　effect　on　writing　performance　with　a　sustained　effect　one　month　later,　and　significant　effects　on　participants’　use　of　the　target　strategy　types　while　non-significant　effects　on　the　non-target　strategy　types.　Analyses　of　the　interview　data　also　uncovered　a　higher　frequency　of　occurrence　and　more　adept　and　deliberate　use　of　the　target　strategies　among　the　experimental　group,　and　offered　tentative　evidence　to　the　differential　intervention　effects　on　participants　of　varied　writing　performance　levels.　Pedagogical　implications　are　discussed.　©　2024