Fraa Lio is a character in the Neal Stephenson novel Anathem.

Fraa Lio is an avout in the decenarian math of the Concent of Saunt Edhar. He was collected at the age of 8 at the same time as Erasmas.

Lio, along with Erasmas, Arsibalt, and Jesry comprise the team which has to physically move a capstan to wind the Great Clock each day during Provener for the seven years prior to the start of the novel.

Erasmas often uses the nickname "thistlehead" for Lio.

Lio is fascinated with the martial arts practiced in the concent at the Ringing Vale, known as vale lore or vlor, and has a bit of an aggressive sense of humor. Militaristic and brave by nature, Lio is recognized by Erasmas as a born leader and more than once finds himself in positions of command.