The purpose of this chapter is twofold (1) to review the benefits of online videogames for promoting second language acquisition (SLA), specifically massive multiplayer online role-playing games (MMORPGs) and (2) to present new research that seeks to explain why and how MMORPGs may be beneficial. The findings from the research indicate that MMORPGs are beneficial to SLA primarily because they provide opportunities for interaction in the target language through participation in collaborative problem solving tasks. The results of the research presented in this chapter show (1) that the requirements of input and output for successful gaming allow for a type of interaction in which the focus on language form leads to modified-output, (2) that players have opportunities to negotiate input as a means of completing in-game tasks, and (3) that in-game tasks are similar to instructional tasks that are believed to be beneficial for SLA in the context of a classroom.