This document summarizes a classroom action research project that investigated using mind maps to improve students' writing skills. The research was conducted from May 1st to May 23rd 2011 at a high school in Boyolali, Indonesia. Two cycles of action research were conducted, each with planning, implementation, observation, and reflection phases. Both qualitative and quantitative data was collected through field notes, questionnaires, interviews, and pre-tests and post-tests. The results showed that students' writing skills improved after using mind maps, as evidenced by an increase in average writing scores from 73.6 to 83.6. The researcher concluded that mind maps are an effective technique for teaching writing.