The number of assaults reported at the Naval Academy rose from 11 to 22, according to the Pentagon's Sexual Assault Prevention and Response Office.
Overall, the number of assaults reported at the three service academies rose from 41 to 65, according to the annual review.
"We know that the military academies are similar to college campuses around the country in that sexual harassment and assault are challenges that all faculty, staff and students need to work to prevent," Maj. Gen. Mary Kay Hertog, director of the Sexual Assault Prevention and Response Office, said in a statement.
The report's authors attributed at least some of the increase in reports to greater awareness of sexual violence and growing confidence in the reporting process.
They described the Naval Academy's prevention programs as "mature and robust" and said the academy was in compliance with Defense Department policies on sexual assault and harassment.
They also highlighted areas for improvement.
The percentage of female midshipmen who said they had been subjected to unwanted sexual contact rose from 8.3 in 2008 to 16.5 in 2010 — nearly one in six. The percentage of male midshipmen reporting such contact rose from 2.4 to 3.4 during the same span.
"While some of this increase may be attributed to more informed midshipmen taking the survey, the rate of unwanted sexual contact for both women and men is far beyond prior measurements at [the Naval Academy] and what is seen at the other two" service academies, the authors wrote.
The Naval Academy "must apply the findings of the 2010 [Service Academy Gender Relations survey] to better focus its prevention programming and address the large increase in the rate of unwanted sexual contact."
An academy spokeswoman said the academy has been using the report to "identify potential improvements to the training and accountability aspects of our program."
"The Naval Academy takes seriously incidents of sexual harassment and unwanted sexual contact — actions which are fundamentally incompatible with our Navy's core values," spokeswoman Deborah Goode said in a statement. "We have zero tolerance for this behavior and our goal is to deter and completely eliminate this unacceptable conduct."
Defense Secretary Leon E. Panetta said that "one sexual assault is one too many."
"This is a leadership issue, first and foremost, so I also expect us to lead with integrity and with energy to eliminate sexual assault and harassment from our culture," he said in a statement. "I'm confident the steps we are taking are the right ones, but we must continue to improve."