Teacher is the most paramount component of the whole teaching learning process and his teach effectiveness and teaching competency produce the best output of teaching learning process. In terms of India; It is widely accepted by scholars and other concerned scholars of different fields such as educationists, sociologist, psychologists, policy-makers, politicians, administrators etc. that in our country there is an unprecedented need for effective teachers to lead the multitudes of school children and adolescents. Effective teachers can contribute significantly in improving standard of the education. For recognizing a good teacher, it becomes essential to identify and estimate some of major patterns of teacher characteristics underlying teacher behavior. Hence, there is keen need for doing research work and understanding various teacher characteristics. A number of researches have been done over so many years, and several questions about teacher effectiveness confronted the researcher while going the literature. There are still a number of unanswered questions. The present investigation is to assess the teacher effectiveness and teaching competency in government senior secondary schools of Gohana city (Haryana) is a small effort on the part of the researcher to make the teacher and teaching more effective. One hundered teachers were taken for the purpose of the present study.Teacher effectiveness scale developed by Dr. Parmod Kumar Mutha and Dr.D.N. Mutha; General Teaching Competency scale by Mr. B.K.Passi and Lalitha were used to collect the pertinent data. After a keen observation it was found that a lot of difference is there in teacher effectiveness and teaching competency of senior secondary school teachers in terms of gender, area and subject discipline.