Technology is increasingly being used to foster engagement, enhance classroom dynamics, promote autonomy and improve the student learning experience in language learning environments. Many teachers have begun to employ digital apps and tools (e.g. Mentimeter and GoSoapBox) as a more interactive alternative to traditional activities. One product that has been particularly popular due to its user-friendly interface and focus on motivation, enjoyment and competition is Kahoot! (https://kahoot.com) -- a game-based student response system in which the teacher takes on the role of a game show host with the students as contenders. Kahoot! can enhance the language classroom by making the introduction of new content (e.g. definitions, tenses or collocations) and the consolidation of knowledge more interactive and visible, helping learners reach mastery of the language content. Although Kahoot! has been a popular platform since its launch in 2013, its utility in the language classroom has yet to be fully explored. Furthermore, to be used effectively, teachers need a clear understanding of its subject-specific affordance and limitations. Therefore, this review explores how language teachers can use Kahoot! to improve student engagement -- and potentially academic performance -- by gamifying learning. Notably, only the free version of Kahoot! is examined.