In learning a foreign language, students’ language input can be obtained through extensive reading (ER) as they have more opportunities to engage with vocabulary and grammar of the language. Many studies have explored the benefits of ER for reading skills, but few discuss about its effect towards students’ grammar. This study focused on the perceptions of 20 Indonesian university students of the practice of ER in learning English grammar. The data was taken from students’ weekly learning log that reports their ER practice and an online questionnaire that probed into their perception about the effectiveness of ER in grammar learning. The study adopted a qualitative approach and content analysis was used to analyze the data. The results show that most students were benefited from ER practice in improving their grammar; however, some reported difficulties in implementing ER. The study recommend implementing ER in students’ English grammar learning.