The Regional School Unit 21 School Board voted this week to allow Arundel students who currently attend Thornton Academy Middle School in Saco to finish middle school there despite the expiration of a 10-year contract this year.

Thornton Academy’s headmaster, however, said both current and future Arundel students should enjoy the same access to the Saco school as in the past, regardless of the contract expiration.

Access for Arundel students to Thornton Academy Middle School has been the subject of dispute for years.

The board of RSU 21, which includes Arundel, Kennebunk and Kennebunkport, voted Monday to allow Arundel students to finish at the private Saco school. In the board’s view, future middle school students from Arundel will attend the Middle School of the Kennebunks.

Thornton Headmaster Rene Menard said in a written statement Wednesday that the board does not have the authority to prevent Arundel students from going to the Saco school. “We look forward to seeing Arundel students on campus this fall and for years to come,” he said.

Arundel students had been attending Thornton Academy Middle School under a 2006 contract developed before Arundel joined RSU 21. The RSU board and Thornton Academy are disputing whether Maine law protects school choice for Arundel students.

The RSU 21 board voted on the issue Monday following a four-hour meeting attended by about 200 people, including many Arundel parents.