ABSTRACT The main purpose of this study was to investigate effects of extensive reading on Ethiopian EFL students’ reading comprehension and attitudes toward reading. To meet this purpose, pretest-posttest comparison group quasi-experimental design was employed. An experimental group (n = 46) and a comparison group (n = 44), selected from two intact grade 8 sections at Taitu Bitul Primary School in North Wollo, Ethiopia, were involved in the study. The comparison class received 200-minute intensive reading instruction per week whereas the experimental class received 120-minute equivalent intensive reading instruction and 80-minute extensive reading instruction per week for 12 weeks. To collect data, reading comprehension tests and attitude questionnaires were administered at pre- and posttests. Both descriptive (mean and standard deviation) and inferential (independent and paired samples t‐test) statistics were used to analyze the data. Independent samples t‐test, and paired samples t‐test were used to determine whether there were significant inter- and intra-group differences on achievement in reading comprehension and attitudes toward reading at .05 alpha level. The results revealed that both the experimental and comparison groups were almost equal in reading comprehension and attitudes toward reading before the intervention. However, after the treatment, the results indicated that the experimental group scored significantly (p<.05) better than the comparison group on posttest in reading comprehension and attitudes toward reading. The findings of the study also showed that the experimental group scored better than the comparison group in both lower-level and higher-level reading comprehension skills after the intervention although the gain scores were not significant in lower-level reading comprehension skills. It was also indicated that the experimental group scored significantly better than the comparison group in both recreational and academic reading attitudes. Based on the results, it can be suggested that integrating extensive reading in input-poor EFL classes significantly contributes to the development of students’ reading comprehension and attitudes toward reading. Implications are thus deduced for EFL curriculum, instruction, and research on extensive reading.