The School Without Walls, a selective D.C. public high school consistently ranked among the nation’s best, failed to fill its incoming freshman class despite receiving a record number of applications this year.

Students had to accept their spots at city schools by May 1, and the Class of 2018 at Walls, as the school is known, ended up about 20 students short of its 139-student enrollment target, according to school system officials.

Walls reopened admissions in an effort to fill the empty seats, and more than 130 eighth-graders took the entrance exam last week, including some who were retaking the test after being rejected the first time.

School system officials attributed the enrollment shortfall at Walls to the city’s shift to a new common enrollment lottery for both traditional and charter schools. For the first time, students filled out one online form to apply to and rank schools they hoped to attend. They were offered admission to one school and were wait-listed only at those they had ranked higher.

The new enrollment system also came with an altered timeline: Students didn’t find out whether they were accepted into Walls until the last day of March, after many private schools required a commitment and deposit.

The School Without Walls, located in a newly renovated building on the GWU campus, is an application-only "honors" high school. (Marvin Joseph/The Washington Post)

School system officials said that they are confident they will find candidates to fill out the class and that the enrollment hiccup is no reflection on the school’s allure.

“We do not believe that there is anything that has changed in terms of the interest of Walls applicants or the caliber of Walls applicants,” said spokeswoman Melissa Salmanowitz. “We’re going to fill the seats.”

It’s not unprecedented for the school to still have a handful of seats available after offering admission to everyone on its waiting list, according to Jean Boland, president of the Home School Association, who has assisted with admissions in the past.

But this year’s episode comes after a turbulent time at Walls, and some parents question whether the school’s reputation has begun to suffer.

For more than a year, parent leaders have been protesting the school system’s decision to merge Walls, which is on the campus of George Washington University, with Francis-Stevens, a K-8 school a mile away.

The merger, announced last year as a way to save under-enrolled Francis-Stevens from closure and create more space at Walls, puts both schools under the leadership of one principal.

Some Walls parents say the merger has left the high school without the leadership it needs because the principal has to focus energy on Francis-Stevens. And they say the notion that Walls students would eventually attend some classes at Francis-Stevens, a proposal school leaders have floated, is unworkable.

Parents and students rallied last month in front of the John A. Wilson Building to raise alarms about the merger’s effect on the school, and an online petition garnered more than 1,000 signatures.

Salmanowitz, the school system spokeswoman, said there is no evidence that the merger had any impact on Walls’ enrollment. Of the more than 1,000 students who applied to Walls, about 550 were deemed qualified to take the admissions test. Of those, 220 passed the admissions interview, and fewer than 180 ranked Walls high enough to be offered admission.

Ed Lazere, a parent who serves as president of the Local School Advisory Team at Walls, said he doesn’t know whether debate over the merger contributed to trouble filling the incoming class.

But “it’s certainly what we as parents have warned about, that to the extent parents are concerned about the quality of the school, they will look elsewhere,” he said.

Brigid McCarthy said her daughter, who will be a junior in the fall, is transferring out of Walls next year because of uneven teaching and disappointment in the school’s management. McCarthy said she was worn out and discouraged by the merger. “It seems to be hurting one of the city’s few high-functioning schools,” she said.

Walls parent John Edgell rejected the notion that the merger has harmed the school, saying it continues to offer D.C. students an unparalleled education.

He blamed the parent group known as the Home School Association for blowing concerns out of proportion and driving potential students away.

“The irony is the HSA set out to try to create changes it thought necessary and ended up trashing the school,” Edgell said. “They let this thing get out of control.”

The mother of one freshman-to-be, Claudia Simons, said her son was admitted to Walls but decided to attend Wilson High School instead. Their decision came down to finding the right school size and fit and had nothing to do with the merger.

“It’s nothing negative at all about Walls,” Simons said. “We were really lucky to have two great options.”

Julie Stewart said her daughter was initially rejected by Walls because her entrance exam was scored incorrectly. Walls officials acknowledged the error and eventually offered admission, but at that point it was too late to spend time visiting the school.

Her daughter also chose Wilson.

“It was just too many disappointments, too many errors and too many missteps by the administration to make her interested anymore,” Stewart said.

School system officials said only three students were affected by the scoring problem.