More than a dozen parents and Readington Middle School students spoke at Tuesday night's board meeting.
Charlotte Nijenhuis, who has a 13-year-old daughter, claims principal Sharon Moffat told her such dresses distract boys.
The Courier News of Bridgewater reports students and parents said the rule should have been clarified earlier because many parents already have purchased their daughters' dresses. Others said that dresses with straps can be even more revealing.
Many parents said it's up to them, not the principal, to determine what their children wear.
The school board will meet May 14.
The June dance is funded by the parents and is held off school grounds.