This article presents the changes in the role of the teacher in classroom education in the 21st century. The 21st century is the century of science and technology. Besides, this is also the era of explosion of knowledge. Information technology has entered and become effective in every field related to human life, due to which the boundaries of knowledge are no longer limited. Due to this, development in every field has been hampered. Education is an important area in all these. Its function is to make classroom teaching effective by the teacher. Therefore, the process of acquiring knowledge by teachers in classrooms has become modern due to science and technology. The teacher who makes this modern education process effective has become a technocrat and facilitator in this century. That is why 21st century education is possible through virtual classrooms and home schooling. So in the presented article, the social values to be maintained by the teacher during classroom education, modernity in the 21st century teacher in the context of classroom education, information technology skills in the 21st century teacher, paper-pencil-less teaching, online teaching-test-evaluation. Role of teacher in, Home school through internet, Role of teacher as online guide, Role of teacher in teaching specific subjects, Teacher in the context of development of multidimensional intelligence, Scientific thought in teacher – Scientific approach – Scientific attitude, Preservation of traditional values and adoption of modern values by the teacher, suggestions towards teacher’s teaching-research-expansion etc. have been included.