Abstrak
This research was done due to several problems that found by the researcher. The first most of students were difficult in memorizing new vocabulary,second the teacher still used conventional method in learning at the classroom, some students said that not interested and the last, most students got difficulties in understanding the meaning of vocabulary. To solve this, researcher offered a solution by using Jumbled Letters game on students’ vocabulary mastery. This game is related to this problem because Jumbled Letters game is enable to help students’ vocabulary mastery. This research aimed to find out the effect of using Jumbled Letters Game toward students’ vocabulary mastery in learning English. This research used a quantitative approach in the form of pre-experimental design aimed to establish a cause-and-effect relationship between an independent and dependent variable. The sample of this research was the 8th grade students at MTs Terpadu Guguak Randah and used purposive sampling technique. In the collecting the data, the instrument of this research was vocabulary test in the form of 25 multiple choice questions and gap filling, which were tested for pre-test and post-test. The data was analyzed by using SPSS 26. Based on the result of this research, the researcher used t-test formula by comparing the post-test score and pre-test score through SPSS 26 by using Paired sample t-test. Based on the output of Statistics the value of Sig. is 0,00 0,05. It means that Ha is accepted. There is a significant difference between students who are taught by using Jumbled Letters Game. The result is also indicated by mean score of post-test result 91,5 is bigger than the pre-test 58,5. It can be sum up, there is a significant effect by using Jumbled Letters Game on students’ vocabulary mastery at grade 8th of MTs Terpadu Guguak Randah.