The aim of this empirical study is to explore O level English language teachersí perceptions regarding teaching practices and methods used in teaching English essay writing. The population of study comprised O Level English language teachers (N=131) schools of Karachi. Through simple random sampling technique, data were collected from (n=58) participant schools which forms approximately 44% of the targeted population. Total sample size was n=73 (n=22 male and n=51 female) teachers. To carry out the cross sectional survey of the chosen sample, two instruments i.e., Factors Affecting English Essay Writing for Teachers (FAEWT) and teachersí structured interviews were developed to collect the quantitative and qualitative data respectively. Data were tabulated, calculated, analyzed, and interpreted through SPSS Version 20, in the light of objectives of the study, and the research hypotheses. Central tendency i.e. mean and measures of dispersions i.e. Standard Deviation and t-test were used for testing hypotheses. Results revealed that students were lacking in understanding the principles of English grammar, difficulty in word spelling and use of punctuation marks in writing essays. On the basis of these findings, it is recommended that Cambridge-affiliated schoolsí management should provide Cambridge professional development training to teachers continually and also provide well-furnished library, language laboratory and classrooms so that teachers can provide quality input to develop studentsí written discourse. This study plays an important role in contributing to researchers, policy makers, curriculum developers, teachers and students to enhance studentsí skills of writing an essay with no errors and coherently.