The aim of this research was to find out the effectiveness of Hangaroo game for teaching vocabulary. This research used quasi experimental involving thirty three students of class VII F as experimental class and thirty four students of class VII A as control class. Hangaroo game was applied in experimental class while control class was taught by using discussion technique. Test was used for collecting the data, namely pre-test and post-test, and the instrument was tried out to some of the seventh grade students of SMP N 3 Purwokerto which was aimed at knowing the validity, realibility, and item difficulty of the instrument. The test consisted of multiple choices items. After data was taken, it was analyzed using t-test formula. The result of t-test computation at the level of significance of 0.05 with degree of freedom 65 = 1.669 was 2.185 which was higher than t-table (1.669), therefore it could be concluded that Hangaroo game was effective for teaching vocabulary at the seventh grade students of SMP N 3 Purwokerto in academic year 2014/2015.