Best Online Co-Op Games on Steam

Unlike generic lists, our strategy game recommendations use a rigorous analysis of Steam user reviews to identify and feature only the best, community-validated online co-op games. For those who prefer not to search, check out lists of the most played, top deals and best free to play Online Co-Op games on Steam.

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Day of Defeat: Source Valve's WWII Multiplayer Classic - Now available for Mac.

Price 9.75€
Rating 9.0
Release 12 Jul 2010
Moonbase Alpha NASA has once again landed on the lunar surface with the goal of colonization, research, and further exploration. Shortly after the return to the Moon, NASA has established a small outpost on the south pole of the moon called Moonbase Alpha.

Price Free to play
Rating 8.8
Release 06 Jul 2010
Alien Breed: Impact Experience the explosive science fiction arcade-shooter that resurrects a much revered franchise in an epic single player and co-op multiplayer campaign.

Price 8.99€
Rating 7.2
Release 03 Jun 2010
Serious Sam HD: The Second Encounter Serious Sam HD: The Second Encounter is a visually upgraded and fully Steam supported remake of the original high-adrenaline single-play and 16-player co-operative arcade-action FPS and Gamespot's Game of the Month!

Price -64% 7.35€
Rating 8.6
Release 28 Apr 2010
Sonic & SEGA All-Stars Racing SONIC AND SEGA ALL-STARS RACE FOR VICTORY IN A HIGH SPEED HIGH SKILL RACETRACK SHOWDOWN! TAKE TO THE TRACK BY CAR, MONSTER TRUCK, BIKE AND EVEN AEROPLANE IN SONIC & SEGA ALL-STARS RACING. Explore stunning new circuits including Sonic Seaside Hill, Curien Mansion and Blizzard Castle as you zip around medieval castle ramparts, hurtle...

Price 9.99€
Rating 8.4
Release 03 Mar 2010
Aliens vs. Predator™ Survive, hunt and prey in the deadly jungles and swamps in distinctly new and thrilling first person gameplay.

Price 14.99€
Rating 8.9
Release 16 Feb 2010
Serious Sam HD: The First Encounter Serious Sam HD: The First Encounter is a visually upgraded and fully Steam supported remake version of the original high-adrenaline single-play and 16-player co-operative arcade-action FPS which was Gamespot's Game of the Year 2001 and which scored overall of 87% on Metacritic!

Price -83% 2.57€
Rating 9.1
Release 24 Nov 2009
Left 4 Dead 2 Set in the zombie apocalypse, Left 4 Dead 2 (L4D2) is the highly anticipated sequel to the award-winning Left 4 Dead, the #1 co-op game of 2008. This co-operative action horror FPS takes you and your friends through the cities, swamps and cemeteries of the Deep South, from Savannah to New Orleans across five expansive campaigns.

Price 9.75€
Rating 9.7
Release 16 Nov 2009
LEGO® Star Wars™ - The Complete Saga Kick Some Brick in I through VI! Play through all six Star Wars movies in one videogame! Adding new characters, new levels, new features and for the first time ever, the chance to build and battle your way through a fun Star Wars galaxy on your PC!

Price 19.50€
Rating 9.4
Release 12 Nov 2009
Call of Duty®: Modern Warfare® 2 (2009) The most-anticipated game of the year and the sequel to the best-selling first-person action game of all time, Modern Warfare 2 continues the gripping and heart-racing action as players face off against a new threat dedicated to bringing the world to the brink of collapse.

Price 19.99€
Rating 9.2
Release 11 Nov 2009
Operation Flashpoint: Dragon Rising Operation Flashpoint: Dragon Rising is a game about a fictitious conflict on one of the Sakhalin islands.

Price 11.33€
Rating 6.7
Release 06 Oct 2009
Resident Evil 5 This game is a port of the Games for Windows - Live version that was released in 2009. If you buy the Untold Stories Bundle here on Steam, it will be the same as upgrading to Resident Evil 5 Gold Edition.

Price -34% 13.23€
Rating 8.6
Release 15 Sep 2009
Nation Red Nation Red is an ultra fast infinite play arena-based shooter providing an exceptional close-quarter battlefield experience. Fight thousands of zombie mutants and their bosses in frantic bloody gameplay while earning close to 100 perks. Fight in Barricade, Survival or Free Play mode.

Price 2.79€
Rating 8.5
Release 03 Sep 2009
Sniper Elite As World War II draws to a close, the first covert battles of the Cold War begin. Caught in the life and death struggle between Soviets and Germans in war-torn Berlin, you control the fate of a lone American OSS Sniper.

Price -96% 0.37€
Rating 7.4
Release 16 Jul 2009
Trine Enchanted Edition Three Heroes make their way through dangers untold in a fairytale world of great castles and strange machinery, featuring physics-based puzzles, beautiful sights and online co-op.

Price -96% 0.61€
Rating 9.3
Release 02 Jul 2009
Killing Floor 6-player co-op survival horror at its finest! Free updates, free special events and a ridiculous amount of fun!

Price -90% 2.06€
Rating 9.3
Release 14 May 2009
Warhammer 40,000: Dawn of War II - Anniversary Edition All of Warhammer 40,000: Dawn of War II in one package. Play the award-winning real-time strategy game in all its glory, including three full campaigns, six multiplayer factions, and a full co-op Last Stand mode with eight unique heroes.

Price 44.99€
Rating 8.6
Release 18 Feb 2009
Saints Row 2 Saints Row 2 brings true freedom to open-world gaming. Players can play as who they want, how they want, and with whomever they want in this sequel to the much acclaimed and tremendously successful Saints Row.

Price -93% 0.79€
Rating 7.4
Release 07 Jan 2009
Call of Duty: World at War Call of Duty is back, redefining war like you've never experienced before. Building on the Call of Duty 4®: Modern Warfare engine, Call of Duty: World at War immerses players into the most gritty and chaotic WWII combat ever experienced.

Price 19.99€
Rating 9.1
Release 18 Nov 2008
Left 4 Dead From Valve (the creators of Counter-Strike, Half-Life and more) comes Left 4 Dead, a co-op action horror game for the PC and Xbox 360 that casts up to four players in an epic struggle for survival against swarming zombie hordes and terrifying mutant monsters.

Price 9.75€
Rating 9.5
Release 17 Nov 2008
Zombie Panic! Source Dive into the zombie apocalypse with Zombie Panic! Source: a cooperative, survival-horror first-person-shooter. A fast-paced standalone modification.

Price Free to play
Rating 8.2
Release 03 Oct 2008
Tom Clancy's Rainbow Six® Vegas 2 Tom Clancy's Rainbow Six® Vegas 2 - the sequel to the award-winning next-generation first-person shooter - returns to Sin City. Tom Clancy's Rainbow Six Vegas 2 is your last chance to rescue America's sexiest city from an escalating terrorist siege that will force you into heart-pounding action from beginning to end.

Price 9.99€
Rating 8.2
Release 16 Apr 2008
Tom Clancy's Rainbow Six® Vegas Tom Clancy's Rainbow Six makes its next-generation hardware debut in the most dramatic installment of the renowned first-person shooter franchise to date. Rainbow operatives take to the chaotic streets of Las Vegas as an escalating terrorist siege in 'Sin City' threatens to take world terrorism to new, uncontrollable heights.

Price 9.99€
Rating 7.6
Release 09 Apr 2008
Team Fortress 2 Nine distinct classes provide a broad range of tactical abilities and personalities. Constantly updated with new game modes, maps, equipment and, most importantly, hats!

Price Free to play
Rating 8.9
Release 10 Oct 2007