The fourth season of the Canadian science fiction–fantasy television series Sanctuary was commissioned by Syfy in January 2010.

In January 2010, Syfy officially renewed Sanctuary for a fourth, 13-episode season, to air starting Autumn 2011.

In describing what the fourth season would be about, Tapping stated the Hollow Earth story line would still be dealt with.

[15] The Sanctuary panel during the 2011 San Diego Comic-Con revealed that there will be a musical episode sometime this season.

[16] The season returned to Friday nights and premiered on October 7, at 10 pm.