Constance McMillen, an 18-year-old lesbian student at a US school who fought for the right to take her girlfriend to her prom, said she was one of only seven students to show up at a private party chaperoned by school officials last Friday night.
She said the rest of her peers went to another private event where she wasn't invited.
Her case drew a national spotlight after she and the American Civil Liberties Union challenged school rules that banned same-sex prom dates.
The ACLU sent a demand letter to Supt Teresa McNeece in February, saying the rules against same-sex prom dates and girls wearing tuxedos violated Ms McMillen's constitutional rights.
Itawamba County School District, Mississippi, responded by withdrawing its sponsorship and cancelling the April 2 event.