The elite Groton School pleaded guilty Monday to failing to report students' sexual abuse complaints to the state.
Groton officials entered the plea on the day the case was scheduled to go to trial. The school was fined $1,250 and avoided a public airing of damaging testimony.
The investigation began in 1999 after the parents of one student told school administrators that he had been sexually assaulted by a group of older male students. Another student later came forward to say that he also had been abused by fellow students.
State law requires school officials, doctors, clergy and others to alert social services of any suspected abuse.
School officials said the student in question did not provide enough information for a report.
Groton School, about 40 miles northwest of Boston, was founded in 1884. Among its alumni is former President Franklin Delano Roosevelt.
The coeducational boarding school has 355 students.
Attorneys for the school did not comment after the hearing in Middlesex Superior Court.