Montgomery County Schools Superintendent Joshua P. Starr says the district will be making changes to address its growing Hispanic population. (Katherine Frey/The Washington Post)

Hispanic students for the first time make up more of Montgomery County’s kindergarten and first-grade classes than children from any other ethnic or racial group, a significant shift that marks the increasing diversity of the high-performing school district.

The fast growth in Hispanic students coincides with a persistent achievement gap in Montgomery, where Hispanic and African American students have long lagged behind their white and Asian American classmates.

Concerns increased for Hispanic students in particular when recent data from SAT college entrance exams showed a 32-point drop in overall scores for Hispanic students, at a time when students from all county groups saw a three-point dip. In the spring, the Montgomery County Council’s Office of Legislative Oversight issued a report showing that fewer than 20 percent of black and Latino eighth-graders scored at advanced levels on 2012 state math exams, while more than 60 percent of white and Asian students did.

The new county numbers, released Tuesday, show that a school system widely known for its affluence and high-achieving high schools is home to a diminishing share of white students and a rapidly growing group of Hispanic students. The latest figures, from September enrollment, show that Hispanic kindergartners and first-graders represent 30.7 percent of students in those grades, outnumbering the next-largest group, non-Hispanic white students, who account for 30 percent.

County school officials first noted the shift with last year’s kindergartners. This year’s enrollment numbers showed the same pattern, in larger numbers, said Bruce Crispell, director of the division of long-range planning for Montgomery schools.

Hispanic kindergartners and first-graders outnumber whites in Montgomery County Public Schools this year, and a third of all students qualify for free and reduced-price meals. (The Washington Post/Montgomery County Public Schools)

Crispell said the figures show the leading edge of a trend he expects to continue over the coming decade.

“It certainly looks as if over time we’re going to become a district where the largest share of enrollment will be Hispanic,” Crispell told the county school board Tuesday, when he presented the data.

In a school system already focused on the achievement gap between racial and ethnic groups, the new numbers may further concentrate attention on students with fewer advantages.

“People continue to think Montgomery County is this wealthy white enclave, but the reality is much different,” said School Superintendent Joshua P. Starr.

In an interview Tuesday, Starr said the school system has a number of efforts aimed at addressing the achievement gap, adding that broad descriptions of student groups mask individual differences. In general, he said, the challenge is “drilling down and knowing every child and having a plan for that child.”

Starr said the district has been actively working on behalf of all students and preparing for the demographic shift: “We don’t need to do anything radically different.”

State Del. Ana Sol Gutierrez (D-Montgomery), who was the first Hispanic member of Montgomery’s school board in the 1990s, said the shift results from “a long-coming phenomenon” and underscores student needs that require more attention.

“I think the school system has been slow to respond and gear up,” she said, commending Starr on his efforts but expressing concern about teacher training, approaches to language issues and the achievement gap. “If we don’t do a better job at educating Latino students, then we’re just not going to be able to keep up high levels of performance in Montgomery County schools.”

Others said Tuesday that Montgomery needs more bilingual teachers and principals as well as a Latino voice on the school board.

Montgomery has about 620 Hispanic teachers, or 5.3 percent of the total, officials said. That number is up from 523 three years earlier. Officials said they have made an effort to focus on such hiring. They did not have data on how many bilingual teachers work in the school system.

The shift comes as Montgomery’s student population has spiked each of the past six years, making it the fastest-growing district in Maryland with 151,607 students this school year. It has added nearly 14,000 students since 2007, and the county projects a total increase of 25,000 students by 2019.

“It’s amazing data,” said Gustavo Torres, executive director of CASA of Maryland, a nonprofit Latino advocacy organization. “This is a big, big change, and I hope the superintendent is going to work hard on this.”

Of 132 elementary schools, Hispanics account for the largest share of enrollment at 45 schools. At 61 schools, whites are the largest group. African American students represent the largest share at 18 elementary schools and Asian students at eight schools.

In Montgomery, overall school data show that across all grade levels, non-Hispanic whites are still the largest group, with 32 percent of enrollment.

Hispanics account for 27.4 percent, African Americans represent 21.4 percent and Asians make up 14.4 percent of students. Students of two or more races account for 4.6 percent.

In addition to the becoming more diverse, Montgomery has experienced a significant rise in poverty within its student population. Nearly 50,000 students — one-third of Montgomery’s enrollment — come from low-income families that qualify for free or subsidized school meals.

The school trends reflect broader ­changes afoot in Montgomery that officials have been tracking for a number of years. In a county of nearly 1 million people, non-Hispanic whites represented less than half of Montgomery residents in the most recent census.

Across the Washington region, other school systems also have seen a marked increase of Hispanic students in recent years. In Fairfax County, 2012 figures show white students at about 42 percent of the enrollment and Hispanic students representing nearly a quarter of the population.

In Prince George’s County, Hispanic students represent about 24 percent of enrollment, and the school system recently hired a diversity officer to focus on Latino affairs.

Nationally, one in four public school students is Hispanic, a milestone crossed in October 2012, said Richard Fry of the Pew Research Center. Non-Hispanic whites account for 51 percent of public school students, African Americans make up 16 percent and all other groups combined represent 8 percent. Fry said that in sheer numbers, public school enrollment growth nationally is driven by Hispanic students.

Montgomery County Council President Nancy Navarro (D-Mid-County), a former school board member, said the new numbers should refocus the district’s attention on student needs, including early-childhood education. “I do believe there is that need to acknowledge who we are,” she said, “and therefore policies and initiatives need to follow.”

T. Rees Shapiro and Ovetta Wiggins contributed to this report.