teachers' training session

Teacher Training Programme

Thank you, enoon.

Suresh

Please tell me why we don't use the apostrophe here.

You can use an apostrophe. Teacher, Teachers, Teacher's and Teachers' are all fine. It's only a matter of how you construe the short version—the training a teacher needs, training for teachers, the training unique to a teacher or teachers. I recommended the simplest version just because it's simplest, on the model of big game hunting.

Thank you, enoon.