This research investigates the effects of the use of Kahoot! to improve English vocabulary learning in an EFL context using a quasi-experimental post-test design. An experimental and a control group from two 9th grade classes participated in the study. A pre- and post-test were applied to both groups and the scores of both groups were compared to determine whether there was any variation. The interventions in each group consisted of two lessons a week for four weeks. In particular, the results of the experimental treatment indicated an improvement regarding English vocabulary knowledge using the Kahoot! app, with a significant variation and a medium effect size. In general, this suggests the necessity of implementing new strategies with the available ICTs at hand to enhance the learning of English in Chilean classrooms.