ABSTRACT Pratiwi, Rosa Sangga. (2023). The Use of Speedy English Grammar Application to Improve Students’ Grammar Mastery at the Seventh Grade of SMP N 12 Magelang. An Undergraduate Thesis. English Education Department, Faculty of Education and Teacher Training, Universitas Tidar. Advisor I Retma Sari, M.Pd., Advisor II Boris Ramadhika, M.Pd. Keywords: Speedy English Grammar, grammar…