The study aims to verify whether extensive reading (ER) is able to promote senior high school students' English reading motivation and foster positive attitude towards reading in English. It further explores the teachers' perceptions of and the challenges faced in the implementation of ER activities. An ER activity was held for 12 weeks with 258 participants from 4 senior high schools in Southern Taiwan. Focus group interviews were then carried out with 72 randomly selected participants, after which individual interviews were conducted with 6 English teachers from these participating schools. Findings reveal that despite the challenges encountered in implementing the activity, the English teachers observed its benefits and were willing to encourage students to read extensively. The majority of the student participants also held positive attitudes towards the ER activity. Their positive attitudes, however, did not lead to the enhancement of their motivation in reading extensively due to the heavy workload from tests, homework or cram school. It was generally agreed that ER was time-consuming and not efficient enough to boost their exam scores. Accordingly, the study suggests that coordinated efforts and change of attitudes among the stakeholders are indispensable in the promotion of ER among senior high school students.