I am a high school vice principal and a mother. I would bring this to the attention of one of the vice principals. Talk to the vp, tell her/him what is going on-be specific. Then ask for a meeting with the vp and the teacher. Make the teacher accountable for his actions and the way he treats children. If your son is experiencing this, it is likely, other students are as well. With the vp apprised of the situation, there cannot be retribution that the teacher throws back at your son. If anything, it should scare him into being especially kind to your son. Good luck.
I was so happy to see Erinn's response, because I had the same thought.
I am a 7th grade teacher, and without any more details regarding the events, I can think of all sorts of explanations for what your son is experiencing, and only one of those explanations would be playing favorites.
One of my first thoughts was that the other student (or students) involved may have IEP [Individual Educational Plans] that are required by law for students with disabilities who require special accommodations and/or modifications.
For example, if I had a student who had special modifications on homework (perhaps doing a limited set of the homework problems), I could certainly see other students thinking I'm playing favorites by giving him full credit for partially-completed homework assignments.
I'd also say that it's quite common for middle schoolers to be particularly concerned about fairness -- and possibly seeing favoritism in just the relationship a teacher may already have with students that the teacher knows from last year.
But teachers are also human, and I know I do get along better with some students than with others. I try very hard not to let that show, as does every other teacher I know. I've also been in classes with teachers who played favorites (and occasionally maybe even benefited from a bit of favoritism.)
Without any specifics of what is actually happening, however, I would probably give things a few weeks to settle down and then reassess. I would probably try to listen to my child's complaints without encouraging them in any way [Responding like "I can see why you would think that is unfair" as opposed to something that might encourage the belief that the teacher is playing favorites--something like "That teacher's behavior is simply unacceptable. I will not stand for that!"]
As others have suggested, though, if you really feel the matter can't wait, you should approach the teacher with an open mind. He or she may have some insights to share about the situation that will change your perspective.
I don't say all of this because I assume the teacher is right, only that it is far more helpful to go in with the approach that you both want what is best for your child, and a teacher has a different point of view on the situation than either you or your son.
Perhaps you should request a meeting with the teacher and the principal together. Especially if the teacher is not responding to your request for a meeting alone. Also I would think that this teacher's supervisor/principal would be interested to know that this teacher is bending/breaking or down right ignoring school rules for certain students. There is a reason the rules are written and provided in a hand book and both students, parents and teachers are expected to follow them. If your son doesn't...he would be expected to be disciplined and the same should go for this teacher. Therefore the supervisor should be aware of what is going on and also if any "retaliation" should happen, I would go back to the principal and/or the superintendent. I have 3 sisters who are all teachers and they have actually been in situations where they helped other students when something like this occurred and sometimes the offending teacher needs to know that people are watching and the behavior improves...there are lots of teachers out there ready to work and California laid off over 1,000 at the beginning of this school year due to budget cuts....They would be happy to take this guy's job and he probably can't afford to lose his...If he is aware he can't get away with the favoritism stuff and any ideas of retaliation...I suspect he will cut out his childish behavior and act like a teacher should. Good Luck
So, your son even had a favorite–the last year’s teacher.
Why not try to win the teacher over with honey rather than vinegar? Volunteer to make calls, be the band 'mom, give the director morning coffee or donuts.
You know how to do it. Do it!