This research aims to investigate the degree of difference in the performance of trained and untrained teachers of English in private secondary Schools of Karachi. This area of investigation has been chosen to ascertain the significance of teacher training in the teaching learning process. The research assesses the performance of ten trained and ten untrained English teachers working at six local schools. The research data is based upon classroom observation, though the informants have been interviewed for the purposes of triangulation. The analysis of the results suggests that in some cases the trained teachers are better than the untrained ones, while in others it is vice versa. The study clarifies certain beliefs and misconceptions such as, only those who are fluent in English can teach the subject etc. The study highlights the relationship between the linguistic and pedagogic competence of the teachers, and the influence of teacher training on them. Many writers use the terms ‘teacher education’, and ‘teacher training’ interchangeably. However, these terms can be distinguished.