The cable channel is scheduled to air 10 new episodes for a fifth season in February 2013.
Last month, Warner Bros TV and TNT were working on a deal that would see the series be brought back for a fifth run.
Southland, which originally aired on NBC before getting picked up by TNT, ended its fourth season in March.
The series follows the lives of police officers working at the Los Angeles Police Department, starring Benjamin McKenzie, Regina King, Michael McGrady, Michael Cudlitz and Tom Everett Scott.
Lucy Liu joined the cast in season four but will not return in the fifth season. The Kill Bill actress is working on the CBS pilot Elementary, a revision of the Sherlock Holmes story.
Watch a promo of Southland's season four finale below: