A federal court judge dismissed a class-action lawsuit Friday against the Boston public schools for routinely delaying the enrollment and evaluation of preschoolers with disabilities.

The School Department prevailed on a procedural issue. Judge Rya W. Zobel said the parents of the two toddlers at the center of the case filed the lawsuit prematurely, having failed to exhaust all other remedies before turning to litigation, as required by federal law.

In issuing her ruling, Zobel did not address the lawsuit’s fundamental question: whether the School Department violated state and federal laws by failing to place preschoolers with disabilities in classrooms as soon as they turn 3 years old, potentially causing regression in the developmental progress they had made.

Superintendent Carol R. Johnson indicated in a statement that she viewed the ruling as a positive development.

“Our commitment to serving students with disabilities has never been stronger,” said Johnson. “In the last two years, we have made substantial changes in how we meet the needs of students with disabilities, and [Friday’s] decision is a strong signal that we are on the right path. There is much more to be done in our efforts to ­reform this important set of work, but we are all in this ­together and we will succeed.”

Massachusetts Advocates for Children, a Boston nonprofit that filed the lawsuit on behalf of the families, has not yet ­decided whether to appeal but will probably seek other courses of action outlined under the federal Individuals with ­Disabilities Education Act, said Michael Vhay, one of the plaintiff’s attorneys.

For instance, the judge said in the ruling that the organization may have better luck establishing a pattern of delayed placements by securing a series of decisions on individual cases from the state Bureau of Special Education Appeals, which then could be used as the basis for a class-action lawsuit, Vhay said.

“It is fair to say we are disappointed in the ruling and the additional delays it will introduce in our effort to solve this problem for all preschoolers,” said Vhay, who is a partner at DLA Piper in Boston. “But we are encouraged that the judge has directed the [state Bureau of Special Education Appeals] to look into the issues we have raised.”

The Boston public schools have struggled to keep pace with a 50 percent surge in the last three years in the number of preschoolers with special needs. The lawsuit said the School Department had “subjected more than 200 preschoolers, some of its most vulnerable youth, to illegal wait-listing.”

Johnson acknowledged in an interview with the Globe earlier this year that the School Department had been slow in placing students but stressed she was remedying the problem. During the past school year, the department added more than a dozen preschool classrooms, including several at a recently shuttered elementary school, as the enrollment of toddlers with disabilities pushed beyond 700.

But Massachusetts Advocates for Children said too many students were still not receiving services guaranteed to them under federal law.