The concern of the study was to explore the effects of integrated reading and writing (IRW) skills instruction on EFL learners' reading comprehension, writing skills and critical thinking skills development at Bahir Dar University. Henceforth, the study employed mixed approaches of quantitative and qualitative research methods to collect and analyze the data in the study. In order to collect the quantitative data, a pre-test/post-test quasi-experimental design was used. Similarly, to supplement the quantitative data results, qualitative data collection instruments like interviews and focus group were employed. In the study, 80 freshman students (n = 40) in experimental and (n = 40) control groups took part in a random assignment. With this in mind, the experimental group received a newly designed integrated reading and writing instruction program for 9 weeks concurrently with 3 sessions per week whereas the control group received separate reading and writing skills instruction. Following that, students' reading comprehension and critical thinking development were assessed using 25 (twenty-five) pre- and post-tests of reading comprehension and critical thinking questions, respectively. In the pre- and post-test composition writing, a five-paragraph essay was used to collect the required data. Hereupon, to determine the reliability and internal consistency of all developed tests, Kappa inter-rater and split-half reliability tests were used. For quantitative data analysis, the data were computed using an independent T-test, ANOVA and MANVOA. Similarly, the qualitative data results were thematically analyzed with respect to each of the dependent variables. Finally, the results of the pre-tests showed that both the control and experimental groups had nearly similar levels of reading comprehension, critical thinking, and composition skills. However, after the intervention, the posttest results indicated that there was a significant disparity between the control and experimental groups in terms of reading comprehension, writing and critical thinking skills development. Briefly, the experimental group surpassed the control group in all three of the above skills in the post-test results. In a nutshell, the aggregate results of the quantitative and qualitative data showed the supremacy of integrated reading and writing skills instruction over the conventional approach in enhancing students‘ reading comprehension, writing skills and critical thinking development. 1 Chapter One Introduction In Ethiopia, English has been used as a language of international communication and a medium of instruction at secondary and tertiary levels. In the country, learning English as a foreign language is closely tied up with a desire to achieve academic success, and to develop communicative competence; it also offers learners a window to look at the world. Apart from this, the present Ethiopian Education and Training policy (1994) addresses that ―the role of English in education and instruction, that it will be taught as a foreign language for cultural and international relations, and it will be the medium of instruction for secondary and higher education, and then it will be taught as a subject starting from grade one‖ (pp.23-24). Despite the fact that English is commonly taught in EFL classrooms, it is still considered a foreign language in Ethiopia. As a result, it is not used as a viable Lingua Franca in the everyday lives of people outside of the EFL classroom. Therefore, in the country, the opportunity to learn and practice English outside the classroom is less frequent. For this reason, more often, students practice the language through reading and writing in their academic careers, regardless of their field of study at the university level. Therefore, developing these skills plays a decisive role in comprehending a reading passage and composing a text efficiently in English at the higher institution level because foreign language development can flourish well even through critical reading and writing a well-organized text. Hence, the instructional methods that EFL instructors use for reading and writing skills must enable students with reasonable levels of language proficiency to develop their expression and reasoning skills to an advanced level to be effective in their academic arena. 1.1 Background of the Study Reading and