The Montgomery County Board of Education voted Tuesday to ask for a 4 percent increase in its budget, citing growing enrollment, continuing costs and efforts to narrow the achievement gap.

The proposed $2.32 billion spending plan for fiscal year 2015 comes in more than $35 million higher than what Superintendent Joshua P. Starr recommended in December. The district mostly attributed the difference to economic provisions related to a tentative agreement with its three employee associations.

Calling the budget request “fair and thoughtful,” board president Phil Kauffman said in a news release that the proposed spending plan “will allow MCPS to keep up with its rapid enrollment growth and invests wisely and strategically to improve teaching and learning.” The district has added almost 14,000 students over the past six years, bringing its total enrollment for this academic year to 151,289 students.

The budget request is also geared toward closing the achievement gap. The spending plan would fund 15 new high-school teaching positions to decrease reading and math class sizes, more staff members to help middle school students learn English and two prekindergarten classes for economically disadvantaged students. The proposed spending plan also accounts for a new program to draw effective teachers to high-needs schools or maintain exemplary teachers already at those schools.

In December, Starr proposed a $2.28 billion budget but “cautioned it should be considered preliminary” because MCPS did not know yet how much state funding it would receive, the district said. Last month, the state gave the district a $13.8 million increase in funding.

Another unknown at the time of Starr’s recommendation was the district’s contract with its three employee associations. The district said it struck a tentative deal for a three-year contract with the unions in the past week.

The board held two public hearings and two work sessions on the budget request in January. Community and board input led to more than $750,000 in proposed funding, including the prekindergarten classes, according to the district.

The Montgomery County Council has the final say on the district’s budget. The council is expected to pass a spending plan in May.