Schools are the first fundamental social institutions in the socalization process. Teachers, especially the first teacher has the second most important role after parents in influencing the children as a result of close relations in a long period. The purpose of this research is to emphasize the socialising role of a teacher and with relation to this role, to present effective method for dealing with undesired behaviours. To achieve these goals first of all socialising roles of teachers with regard to education levels are reviewed. Limitations of teachers' roles are examined and effective methods to deal with undesired behaviours within such limitations are presented.