Production on the fresh run of episodes is to begin in Toronto in August.
Starring Grant Bowler, Julie Benz, Stephanie Leonidas, Tony Curran, Jaime Murray, Graham Greene and Mia Kirshner, the show is to return in 2014.
"Bringing the rich world of 'Defiance' to life has been in incredible team effort. We couldn't ask for better partners than [show-runner] Kevin Murphy, his amazing cast and crew, and Trion Worlds," Mark Stern, Syfy's president of original content, said in a statement Friday. "We can't wait to see where they take us in the second season."
"Defiance" is a collaboration between Syfy and Trion Worlds, creators of an online game related to the television program.
"Set in the near future, 'Defiance' features an exotically transformed planet Earth, its landscapes permanently altered following the sudden -- and tumultuous -- arrival of seven unique alien races," a synopsis said. "In this somewhat unknown and unpredictable landscape, the richly diverse, newly-formed civilization of humans and aliens must learn to co-exist peacefully. Each week, viewers follow an immersive character drama set in the boom-town of Defiance, which sits atop the ruins of St. Louis, Missouri, while in the game, players will experience the new frontier of the San Francisco Bay area."