Parents, students and elected leaders from Montgomery County plan to join forces in Annapolis Thursday night to press for more state construction funding for Maryland’s fastest-growing school system.

Montgomery’s PTA leaders have rented five buses to help get hundreds of people to the evening events, which include a briefing, reception, rally and other activities intended as a show of advocacy for Montgomery. It coincides with a Maryland PTA Night in Annapolis.

Janette Gilman, president of the Montgomery County Council of Parent-Teacher Associations, said organizers expect 250 to 350 people and are hoping to send a strong message about Montgomery’s crowded schools and critical need.

“If we don’t get this money, I don’t know where were going to put the kids,” she said, adding that many schools already have playground blacktops occupied by portable classroom trailers.

Montgomery elected leaders have long complained that the school system accounts for 17 percent of the state’s student enrollment but has received about 11 percent of recent state construction funding. Montgomery should get its “fair share,” they have argued.

But Montgomery’s schools also are surging with new enrollment, up by 14,000 students since 2007 — and increasingly leaders and advocates have been vocal about the need to relieve overcrowding. Montgomery is the state’s largest district, with 151,300 students.

Another 11,000 students will come into county schools during the next six years, according to projections.

Superintendent Joshua P. Starr cited lack of state funding as an issue when he proposed a $1.55 billion capital improvement budget in the fall. More recently, school construction was a major focus of County Executive Isiah Leggett’s capital improvement plan.

Montgomery PTA leaders say they hope to be joined by at least two school board members, four county council members and Leggett on Thursday night.

In addition to the PTA-funded buses, Walter Johnson High School in Bethesda is sending a bus, with students and a teacher, from a leadership class, Gilman said.

Montgomery PTA leaders also lobbied in the state capital in January, shortly after the legislative session opened.