Behavioral therapy involves helping to promote positive behaviors and discourage unwanted ones.
The one you will hear most about is called Applied Behavior Analysis (ABA) Therapy.
What is ABA Therapy?
It has been shown to be one of the most helpful therapies for children with autism, but there is also some criticism from some parents and autistic adults. (See article below.)
Its goal is to help kids improve behaviors and social skills through 1-on-1 sessions and group play; to overcome behaviors that get in the way of healthy development; and learn to use positive alternatives.
The therapist gets to know the child's strengths and motivating factors to help encourage positive behaviors.
It creates and uses a set of strategies that help that child to react positively to their environment and situations.
Sometimes, however, ABA therapists will try to train kids out of behaviors that are useful and grounding for them, or are just a way of interacting with their world that happens to be different than most ("neurotypical") people.
Be involved in what an ABA therapist is working on with your child, and make sure you and your child feel comfortable with the goals and methods.
There are also other types of behavioral therapy.
Source: Centers for Disease Control (CDC)