Adelia Antoinette Field Johnston (February 5, 1837 – July 22, 1910) was an American educator and college administrator.

She was the first female faculty member at Oberlin College, where she taught history, and the school's Dean of Women from 1870 to 1900.

[1] At age 13, she taught school for three weeks, while the assigned adult teacher was ill with measles.

[3] Johnston was also active in the town of Oberlin, Ohio, holding art exhibitions, supporting a natural history club, and cleaning up unsightly lots in the town as a founder of the Oberlin Village Improvement Society.

[1] Adelia Field married fellow Oberlin alumnus James Mix Johnston in 1859; he died in 1862.