Does an employer have to insure your children until they are 24 years-old if they are a full-time student?

You need to read the policy. Many factors will influence the answer. It is up to the insurance policy whether or not the child is classified as a dependent. Mississippi treats children as dependents until they are 25 but it is an odd state and that was 10 yerars ago to the best of my knowledge and recollection. Most states leave it at 18 and let the employer and insurance company negotiate anything over that age. So long as they treat all employees equally, it is up to the company and their insurance company to decide what benefits they choose to provide and at what cost.