The plan was to open the capsule in 2006 to mark the 25th anniversary. Alumni say the Long Island school has told them the capsule is missing.
The capsule included Smurf dolls, a Rubik's Cube, baseball cards and other mementos.
It was buried in an area that was paved over in the mid-1990s. It was supposedly removed for safekeeping.
One alum, who's now 39, has started a Facebook page, "Hand Over the Berry Hill School Time Capsule!"
A school spokeswoman says administrators are looking into the issue.
NEW YORK AND TRI-STATE AREA NEWS