This study has been prepared with the aim of to find out the (a) relationship between online games and vocabulary learning and (b) whether gender effects vocabulary learning through the online games. As one of the outcomes of technology, computer assisted language learning (CALL) increased the popularity of using computers in the classroom environments as a tool for learning languages. Along with the development of internet, the games started to appear in the form of online games. Correlatively this paper investigated five international articles related to online games and vocabulary learning from Iran, Turkey and China in which different methods have been employed including quantitative and qualitative measurements. The evaluation of the articles showed that adopting online games in language teaching for vocabulary learning is more efficient than rote learning; however the success depends on the gender. Male students do better in gaining vocabulary through online games comparing to female learners.