Valenzuela, who was elected in 2017, announced her resignation in a letter to the board of trustees that will be presented at a Dec. 5 meeting.
"It has been a true privilege to serve alongside each member of the board, and it has been amongst the greatest honors of my life to serve the children of Carrollton-Farmers Branch Independent School District,” Valenzuela wrote in the letter.
She is seeking election to the U.S. House of Representatives for Texas’ 24th Congressional District. The seat is left vacant by U.S. Rep. Kenny Marchant, R-TX, who announced he would not seek reelection in August.
"We've got all of these great things happening in the school district, but we're struggling to keep kids in their seats, and that's largely because the cost of living is far outpacing wages and salaries," Valenzuela said in an interview.
She said she chose to resign to run for Congress to continue working for that same group of people.
"This is the best leverage I have for our kids right now," Valenzuela said. "It hurts, though."
Editor's note: This story will be updated as more information becomes available.