How do you respond when your little girl tells you all the kids at school are mean to her?

I would ask what they did and how she reacted. I think it would be good to understand if the other children are "just playing" or had malicious intent. If it were the former, I would teach the child to try and stand up for herself and tell the other children that she did not like being treated this way. If it is the latter, I would probably ask her to report to the teacher the next time it happens. On my end, I would speak to the teachers to get them to keep a lookout for such behaviour. I think if there are children in the school displaying "bullying" behaviour, that should be addressed and the best person to do it would be the teachers who can intervene when the incident happened. Hope this helps!