Henry Clay Allen (March 19, 1838 – October 31, 1889) was a Virginia lawyer and politician.

He represented Shenandoah County in the Virginia House of Delegates, and served as that body's Speaker from 1877 until 1879.

During the American Civil War, he, his brothers and cousins all enlisted in the Confederate States Army.

After the war, Allen returned to the Shenandoah Valley, where his grandfather had practiced law as well as served as a judge.

When Democrat Grover Cleveland became president, Allen was the United States Attorney for the Western District of Virginia from 1885 until 1889.