The research of this thesis was conducted at MTs Miftahul Huda Dongos on the seventh grade students. The researcher would like to know the students’ improvement in learning writing skill in teaching by using Grammar Translation Method. The research objective are: (1) To find out the significant difference in writing achievement between the students who are taught using grammar translation method and those who are not. There were some students’ problem that the researcher found. The problems were about students’ ability in mastering aspect of writing and also the students’ study habits. In this research, the researcher conducted experimental research. The population of this research is students of seventh grade of MTs Miftahul Huda Dongos. The subject of the study is 7A and 7B. 7A is chosen as the controlled class and 7B as the experiment class. The result of data analysis using t-test showed, the value of to was 5,556. By using degree of freedom 5%, the value 66 (the degree of significance) as stated in the tt was 1,668. It means that the result from this calculation to>tt (to is higher than tt). Therefore, the Null Hypothesis (Ho) is rejected and Alternative Hypothesis (Ha) is accepted. It means that there is a significant difference between of students achievement in writing skill between students who are taught by using grammar translation method and students who are taught without using grammar translation method. The mean score of students post-test in experimental class is higher than in controlled class. It means that the use of grammar translation method is effective in teaching writing skill.