This research is an experimental study with a pretest-posttest design.Variable in this study is a scaffolding technique, mind mapping, and expository narrative writing ability. Scaffolding techniques is learning by providing assistance to students in the form of narrative models, map content, sentence cards, and guided writing. Mind mapping is a technique of learning by noting mind maps into a blank paper, and then elicits the mind map into paragraphs. The population in this study is students’ ability of Eight Grade SMP Negeri 1 Rembangpurbalingga. By using purposive sampling technique, the sample of the study is VIIIG (experimental class 1) and VIIIB (experimental class 2). A data collection technique is in the form of a written test. Techniques of data analysis performed using t-test with respect to conditions of normality and homogeneity. The results showed an increase in students' ability to write expository narrative after the application of scaffolding techniques and mind mapping. Scaffolding techniques improve average from 61.40 to 67.50. Mind mapping techniques improve average from 62.40 to 69.40. Application of both techniques increased activeness, enthusiasm, and motivation of the students wrote. Results of t-test scores the experimental group 1 produces t-count of 11.140 with 33 df and t-table (ttb) 2.042 at significance level of 5%. Thus, scaffolding and mind mapping techniques effectively improve the ability to write expository narrative. Results of t-test scores posttest experimental group 1 and experimental group 2 producing t-test of 0.583 with 36 df and t-table 2.000 at significance level of 5%, meaning that the value of t-test is less than t-table (t-test: 0.583 < t-table: 2.000). It shows that there is no difference in the ability to write expository narrative significance between using scaffolding techniques and mind mapping.