The thesis is entitled “The Effectivenes of the Combination of Numbered Head Together (NHT) and Crossword Puzzles on Students’ Vocabulary Mastery” (A True Experimental Research at Eight Grade Students of SMP Negeri 1 Batealit Jepara in the Academic Year of 2018/2019). The objective of this research is to see whether or not the combination of Numbered Head Together (NHT) and Crossword Puzzles method is effective in improving students’ vocabulary at SMPN 01 Batealit Jepara.In this research, the researcher used quantitative approach in the form of true experimental research design. The population of this research are the eighth graders with the total 183 students and the sample of this research were 55 students that divided in toexperimental class (8A=27 students) and control class (8F= 28 students).The experimental class was students which were taught by the combination of NHT and Crosssword Puzzle while control class was students which were taugh by conventional method in the form speach and discussion method.The data were obtained by test which were divided into pre-test and post-test and the data were analyzed by using SPSS 16.0 for windows. The result of this research showed the pre-test scores (experimental class was 70.1 and control class was 72.14) and the t-test of pre-test showed sig. (2-tailed) > 0.05 ( 0.313> 0.05) it means that the data not significant. In the post-test (experimental class was 77.40 and control class was 74.28) and the t-test of pre-test showed sig. (2-tailed) < 0.05 ( 0.049 < 0.05) it means that there was significance between experimental and control class. Beside that, the score of tobserve was 2.012 while score of ttable was 2.000. It shows that tobserve > ttable = 2.012 > 2.000 in the degree significance 5%. It means that the Alternative (Ha) was accepted. It can be conclude that the Combination of NHT and Crossword Puzzle is effective in improving students’ vocabulary mastery. It could be solution for the teacher in teaching vocabulary using the combination of NHT and Crossword Puzzles as a method.