This exploratory study is an action research that sought to improve the report writing skills of Science II students of Subic National High School (SNHS) using Reflective Journal Writing Technique (RJWT) as the main strategy to be utilized. Pre-test and post-test were administered prior and after the application of RJWT to gauge its effectiveness on the level of report writing skills of the Science II students. The results of the students' written quizzes, journal entries, laboratory reports and other written outputs were gathered and analyzed to mark the changes on their improvement. RJWT was applied through the M-E-N-T-O-R steps formulated by the teacher: (a) Motivate through reflective questioning; (b) Execute the lesson through concept formation; (c) Note students' participation in the discussion; (d) Team the students for reality check reflection; (e) Offer time for outputting; and (f) Run and monitor small group writing sessions. The study concluded that there was a significant change in the report writing skills of the students after the application of the Reflective Journal Writing Technique (RJWT).