This study aimed to investigate the use of the extensive reading (ER) approach in affecting students reading rate words per minute (WPM) in Indonesian secondary EFL students. This study applied a qualitative research design, and the approach was the case study research. This study took 3 (three) students of XI-grade science class in one of the senior high schools in Sukoharjo, Central Java, Indonesia, that had been selected by the teacher based on the daily scores: high, medium, and low scores. The data were collected through classroom observations, interviews, and documentation. The data were analyzed using the interactive model. The results showed that the English teacher used some approaches to increase the students' reading rates during the process of teaching reading. The study also revealed that using an extensive reading (ER) approach had many positive effects, especially increasing the number of words-per-minute (WPM) of EFL students in reading. The findings indicated that extensive reading positively impacted the affective spaces of reading, such as attitudes and motivation for EFL students to read English text. Furthermore, this study had implications that extensive reading (ER) was an effective activity to boost and increase students' interest in reading and improve their reading rates. As a result, EFL students would become good readers in the future and be able to easily understand the meaning of the text when they have read it.