A deal was reached Wednesday night after Washington Gov. Christine Gregoire ordered both sides back to the bargaining table, school officials said.
The union and school district negotiated for more than six hours in the governor's office Wednesday before reaching an agreement.
"I'm pleased that a tentative agreement was reached tonight and that kids will be back in school on Friday," Gregoire said in a statement. "This agreement provides a long-term solution, meets the districts needs and ensures teachers remain proud to report to their classroom every day."
The district's nearly 2,000 teachers were scheduled to vote on the deal Thursday.
A state judge last week had ordered the two sides to resume negotiations and ordered teachers back into the classroom, CNN said.
The strike kept 28,000 children out of the classroom for more than a week.