Related services are the supportive services that help a child actually benefit from their special education. The list is broad: speech-language therapy, occupational and physical therapy, counseling, school health services, orientation and mobility, and transportation, among others. If a service is needed for your child to access and make progress in their program, it can belong on the IEP.
The key phrase is "needed to benefit." These services are not add-ons a school can hand out or withhold at will; they are required when a child needs them to receive an appropriate education. That is why the evaluation matters — it should identify not just the disability but the specific supports that follow from it. A gap between what the evaluation shows and what the plan provides is worth questioning.
As with every service, watch for specifics on the IEP. Each related service should list its frequency, duration, and setting — for example, thirty minutes twice a week in a small group. "As needed" or "consult" with no numbers is a soft promise. If you believe your child needs a related service they are not getting, you can ask the team to evaluate and add it.
General information and document preparation — not legal advice.