The aim of this research was to find out the effectiveness of hot seat game for teaching vocabulary at eighth grade students of SMP Negeri 3 Purwokerto in academic year 2014/2015. This research used quasi experimental research involving thirty four students of class VIII F as experimental class and thirty four students of class VIII G as control class. Hot seat game was applied in experimental class while control class was not given any special treatment. Test was used to collect the data, namely pre-test and post-test. The test consisted of multiple choice items, scrambled sentences items, and scrambled words items. After data was taken, it was analyzed using t-test formula. The result of t-test computation was 2.958, and the value of t-table at the level significance 0.05 with degree of freedom 66 was 1.668. Thus, the result of t-test computation was higher than the value of t-table (2.958 > 1.668), and it means that the hypothesis was accepted. Therefore, it could be concluded that hot seat game was effective for teaching vocabulary at eighth grade students of SMP Negeri 3 Purwokerto in academic year 2014/2015.