Nathaniel Stephen Appleby (February 27, 1820 – after 1883) was an Ontario businessman and political figure. He represented Hastings East in the Legislative Assembly of Ontario as an independent Conservative from 1875 to 1883.
He was born in Prince Edward County, Upper Canada in 1820, the son of Thomas Dorland Appleby, and educated in Belleville. He operated flour mills near Shannonville. In 1842, he married Sarah Maria Lewis. Appleby was reeve for Tyendinaga Township from 1851 to 1870 and warden for Hastings County from 1858 to 1862. He also served as justice of the peace. He was defeated by William Parker Hudson for the Hastings East seat in 1883.