Lily Doyle was among 11 students asked to leave the prom, which was held in May. Most of the other students are also special needs.
An aide told the group that they would be leaving about an hour before the prom concluded even though a limo had been reserved and was scheduled to arrive around the time the prom was supposed to end.
The school district later apologized for the incident.
The lawsuit, filed in Somerset County Superior Court by Doyle's mother, alleges Doyle was discriminated against because of her disability. The Red Bank law firm of McOmber and McOmber is representing the family.
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