This thesis is entitled The Effectiveness of Using Spinner in Teaching Vocabulary (An Experimental Research at Seventh Grade Students of MTs Mambaul Ulum Mambak Pakis Aji Jepara in Academic Year2018/2019). The purpose of this research was to get empirical data that spinner is effective in improving students’ vocabulary. This research was held in August 2018 in MTs Mambaul Ulum Mambak Pakis Aji Jepara. The method of this research was quantitative research that was quasi experimental design. There were two classes were taken as subject of this research, namely experimental group and control group. The experimental group was VII A and control group was VII B. in analyzing the data, the writer used a quantitative measurement to get the result. The data showed that there is significant different after using spinner and without using spinner. The average score of the students is 61.13 (experimental group) and 60.15 (control group). Based on this data, using spinner could be used in improving students’ vocabulary mastery. The result used t-test shows at the significant level 5% and 1%.the result of t-test > t-table (3.797 > 1.674-1.299). Based on the above, there is significant difference between students’ vocabulary using spinner and without using spinner. It concluded that using spinner in teaching English can improve students’ vocabulary of MTs Mambaul Ulum Mambak Pakis Aji Jepara.