Writing is a challenging skill for learners learning English as a foreign language. When writing English, students face many problems triggered by a lack of knowledge of the English language, interference with their mother tongue, and difficulties related to vocabulary and grammar usage. One particular demanding aspect of writing is attaining coherence and text harmony. Literature indicates that many second language learners tend to underuse, misuse, or overuse cohesive devices, which is crucial in maintaining coherence and cohesion in academic writing. This research focused on evaluating the use of cohesive devices in the academic writing of undergraduates majoring in English at Islamia College Peshawar. Data were gathered through student-written essays on IELTS test topics, with 30 randomly selected samples from each of the 4th, 6th, and 8th semesters, totaling 90 samples. Employing both quantitative and qualitative methods, the analysis revealed a prevalent issue: the inaccurate utilization of various cohesive devices. Students demonstrated an understanding of structuring discussion texts coherently, yet their challenges stemmed from the misapplication of cohesive devices, leading to incomprehensible texts. This study explored lexical and grammatical cohesion, leading to the recommendation that future research should embrace aspects like sentence structure, tense usage, and alternative cohesive models.