Freeman Tulley Knowles (October 10, 1846 – June 1, 1910) was a veteran of the American Civil War, lawyer, journalist and social activist.

Knowles was born in Harmony, Maine, and educated at the local schools and Bloomfield Academy in Skowhegan.

After the war Knowles moved to Denison, Iowa, where he studied law and attained admission to the bar.

Knowles later became involved with the Socialist Party of America, and made unsuccessful runs for Governor of South Dakota in 1904 and 1906.

In addition, he started a socialist newspaper, The Lantern, and his editorials and stories on topics including birth control, labor rights, and labor unions angered mine owners and other business leaders, which resulted in scrutiny by law enforcement agencies and other government officials.