This research aimed to determine the effect of a methodology based on the web platform "Jungle English" on the development level of grammatical learning of the English language of students of the I and II cycle of the Professional School of Languages of the National University of San Martin - T, 2019. The type of research was applied with an experimental level and a pre-experimental design with pre- and post-test. The sample consisted of 38 students. The instrument used consisted of 118 questions based on grammatical content. The results showed that the level of development of grammatical learning before the application of a methodology based on the "Jungle English" web platform was deficient, since 55% of the students (21) had grades between 0 and 10. Likewise, the level of development of grammatical learning after the application of a methodology based on the "Jungle English" web platf...