Frank Kershner Dunn[1] (November 13, 1854 – August 8, 1940) was an American lawyer and judge, who was thrice elected to the Illinois Supreme Court, serving from 1907 to 1933.

Born in Mount Gilead, Ohio, Dunn received his bachelor's degree from Kenyon College in 1873 and his law degree from Harvard Law School in 1875.

In 1878, Dunn moved to Charleston, Illinois where he continued to practice law.

In 1897, Dunn was elected an Illinois circuit court judge.

Dunn died at his home in Charleston, Illinois after a long illness.