The aim of this research was to know whether cross word puzzle game is effective
to improve students’ vocabulary mastery or not at the second grade of junior high
school. Research participant consisted of 60 students in second grade of junior
high school at SMP Muhammadiyah 1 Purwokerto. This research used quasi
experiment method. Two classes were selected as an experimental and control
group. In collecting the data this research used test as the instrument. After
getting the data, this research used t-test computation to analyze the data. Based
on the result of the data analyzed, it was found the result of t-test was 4.48, while
the t-table score at the significant level