This study aims to determine the effects of educational computer games on the tenth grades students' academic achievement and attitudes towards the course. The research was conducted with 60 tenth-grade students attending an Anatolian high school during the school year of 2019-2020. The study was designed as a quasi-experimental design with a pre and post-test experiment and control group. The subjects were taught through traditional teaching activities based on the English education program in the control group while educational computer games were used as teaching activities in the experiment group. The academic achievement test (Kr-20 = 0,83) and attitudes towards English scale (Cronbach's Alpha = 0.95) were conducted as the pre and post-test. Data analyses showed that the experimental group performed better than the control group in academic achievement test. However, there is no statically significant difference between two groups in term of attitudes towards English. The results suggest that computer game can be used in education as an ICT tool to increase students' academic success in English learning.