To dream about your teacher means that you have decent respect for this person. Sometimes the teacher is interpreted as the good example which gives you the will to be just as him or her. The teacher could be like a metaphor of the person you are learning from and who has a big influence in your life. To dream that you are the one who is a teacher but in reality is not could indicate your desire to become one or the fact that you want to teach others something.
Read more about dreaming of Teacher in other dream meanings interpretations.