The purpose of the research is to investigate the effect of clustering technique towards students" achievement in writing paragraph of the second grade students of SMAN 1 Kuala Tungkal. In this research, students are expected to be able to write descriptive and recount paragraph by using clustering technique. The method used in this research is quasi experimental method. Since some factors that could influence, the result of the research is ignoring. The data are taken by administering progressive test and post-test. In this case, students of both groups are asked to write paragraph based on topic given by using clustering technique (for experimental group) and free writing (control group). The population of the research is all second graders of SMAN 1 Kuala Tungkal. For this research, simple random sampling was used as the sampling method. Moreover, there were some steps in analyzing the data: comparing mean scores of progressive test of both groups, comparing the value of t-calculated to the table. Based on the data analysis, the data of progressive test shows that the mean score of overall meetings which is caused by clustering technique was 9.97 while by free writing technique is 8.09. Furthermore, clustering technique has given differentt effect; it is 3.92 (based on t-test calculation). A single blue line can be drawn that clustering technique gives effect on students? writing.