All children are the target of teasing and name-calling at one point or another. Children with Attention Deficit Hyperactivity Disorder (ADHD) tend to encounter more of this than most children, due in part to their problem with interpreting social cues from other children and also as a result of some typical ADHD behavior.
Many adults will encourage a child to just "forget about it" when they encounter teasing, but it's not that simple, especially for a child with ADHD. Their self-esteem may be constantly taking hits from adults who are annoyed by their behavior, so peer acceptance is probably more critical to their emotional well-being than that of a child who does not have a disorder. So it's really important to get to the root of the cause for the teasing and help your child to find a constructive way to handle it.
If ADHD Behaviors are Causing Teasing
Children with ADHD are frequently the target of teasing because of specific ADHD behaviors like incessant talking, interrupting, bragging, bossiness, impulsivity and overall hyperactivity. These behaviors tend to have a negative impact on their relationships with other children. While there's no way to make these behaviors disappear, social skills training can help.
Also, children with ADHD often make themselves a more attractive target for teasing because they tend to overreact to it. Even good-natured teasing can escalate if the target gets defensive and upset.
Simply pointing out to your child that reacting to teasing may fan the flames and keep it going longer may help him to keep cool next time. In addition, you might want to brainstorm some comebacks with your child and roleplay them to ensure that he's more likely to react that way next time. The goal is to help your child stand up to teasing without overreacting and getting upset.
I also tell my son that this is the one time that I'll condone saying, "Whatever," which I normally hate. (I think it's the ultimate in passive-aggressive.) But in this case, I tell him that it's fine to say, "Whatever" with a smile on your face and move on to something or someone else.
Inability to Read Social Cues
Was your child teased or insulted by a child he's friends with? If so, it's possible that the child lashed out verbally in response to something your child did. My son came home one time upset that a friend of his (let's call him Jason) had called him a jerk. I was surprised, since I knew Jason, and my experience was that he was a very nice kid. With a little probing, I found out that my son had been roughhousing with Jason. Initially my son insisted that Jason was on board with it, but with a little probing I found out that Jason had told him to stop, but my son, as is the case with many children with ADHD, had missed any social cue that he wasn't hit over the head with.
I pointed out to him that Jason's reaction was actually a fairly reasonable one, since he was frustrated by my son's refusal, conscious or not, to respect his wishes. I also told him that "jerk" in that case probably referred more to his behavior at that particular moment than an overall indictment of his character. I did some role-playing with my son telling him to stop doing something in different ways, from subtle (facial expression) all the way to yelling "Stop!" We also discussed how it could be possible that another child might be fine with roughhousing (or another activity) initially, but then want to stop, and he should watch for those cues.