Choate Rosemary Hall, an elite boarding school in Wallingford, Conn., acknowledged decades of sexual abuse by former teachers against the students entrusted to their care in a report on Thursday.

The report, written for the board of trustees by an investigator at the law firm Covington & Burling LLP, documented the actions of at least 12 former faculty members, beginning in the 1960s and into the 2010s. The claims of abuse include instances of “intimate kissing,” “sexual intercourse” and “forced or coerced intercourse.”

The report said that no current faculty members were implicated in abuse and that there were no reports relating to current students. In some cases, administrators had written letters of recommendation for teachers who resigned after being confronted with evidence of misconduct.

“Our interviews and school records showed that sometimes the school moved quickly and decisively,” the report said. “In other cases, it was slower to respond and allowed the faculty member to remain at the school, sometimes with restrictions on his or her activity, for a considerable length of time.”

Choate is a rarefied boarding school in Connecticut whose blue-blooded alumni include President John F. Kennedy and his brother Joseph P. Kennedy Jr. It joins a string of prestigious private schools that have faced accusations of sexual abuse by faculty members. St. George’s School, in Rhode Island, announced in 2015 that it was investigating “multiple credible reports” of sexual abuse against its students in the 1970s and ’80s. Horace Mann and Poly Prep, private schools in New York City, have also been confronted with abuse claims.

Paul Mones, a lawyer who represents victims of sexual abuse, said private schools can be particularly prone to such attacks.

“They are closed systems, especially residential private schools where kids are separated from their parents,” Mr. Mones said. “It’s not like a public school with people coming in and out all the time. There are many more opportunities for teachers to do this.”

Document | Report to the Board of Trustees of Choate Rosemary Hall Written by an investigator at the law firm Covington & Burling LLP, the report documented the actions of at least 12 former faculty members, beginning in the 1960s and into the 2010s

The report on Choate said the school kept accusations of sexual misconduct from being publicized for years. “Sexual misconduct matters were handled internally and quietly,” it said. “Even when a teacher was terminated or resigned in the middle of the school year because he or she had engaged in sexual misconduct with a student, the rest of the faculty was told little and sometimes nothing about the teacher’s departure and, when told, was cautioned to say nothing about the situation if asked.”

Cheyenne Montgomery, who graduated from Choate in 1992, was abused by two teachers named in the report. In a telephone interview, Ms. Montgomery described herself as an unusual Choate student because she had very little money.

A math teacher encouraged students to come to him for extra help, and during her sophomore year, he suggested she visit him to study, she recounted.

“Conversations with him started getting more personal,” she said. “He started kind of sharing information about himself and digging into information about me, mostly about my father, and kind of through that, it developed into what felt to me like a boyfriend-girlfriend situation. And it became physical.”

He resigned at the end of the school year.

During her senior year, she was abused again, this time by a French teacher. Shortly after Ms. Montgomery graduated, Choate learned of the relationship. The report said this prompted the teacher’s “departure from the school at the end of that academic year. He then returned to the Kent School, where he had taught before joining the Choate faculty, and from which he retired in 2013.”

Ms. Montgomery recounted her experience to The Boston Globe in 2016.

In a letter to members of the school community, Michael J. Carr, the chairman of the board of trustees, and Alex D. Curtis, the headmaster, said: “On behalf of Choate Rosemary Hall, we profoundly apologize. We honor and thank the survivors of sexual misconduct who came forward. We extend our deepest apologies most specifically to all survivors of sexual misconduct and their loved ones.”

Ms. Montgomery described the report as an important step, but said there was much more work to be done.

“These things were really embedded in the culture, and not just at Choate,” she said. “A lot of progress has been made, but we can’t feel like we’ve just tied this up into a tidy little gift and said, ‘It’s in the past.’ We’re talking about the past because we have to deal with this in the present.”