The third season of the American science fiction television series Fringe began airing on the Fox network on September 23, 2010, and concluded on May 6, 2011.

Twenty-two episodes long, the season was produced by Bad Robot Productions in association with Warner Bros. Television, and its showrunners were Jeff Pinkner and J. H. Wyman.

Lead actors Anna Torv, John Noble, and Joshua Jackson reprised their roles as FBI agent Olivia Dunham and the father-son duo Walter and Peter Bishop.

Previous series regulars Lance Reddick, Jasika Nicole, and Blair Brown also returned, along with recurring guest stars Kirk Acevedo, Seth Gabel, and Ryan McDonald.

The nineteenth episode, "Lysergic Acid Diethylamide", contained long sequences of animation in order to accommodate guest actor Leonard Nimoy's retirement from acting.

While the writers had attempted to continue the idea of the "mythalone" for both casual and devoted fans, Fringe mythology became more visible in the last episodes of the season.

Reviewers reacted well to the exploration of the parallel universe, and the performances of Torv and Noble, who each played differing versions of their original characters, were lauded.

They are unaware that Fauxlivia has replaced Olivia, and she works to help the Fringe Division to identify the components hidden across the globe for a similar Wave Form Device in the prime universe.

After this experience, Peter uses the device to link the two together, fusing the two rooms from the prime and parallel universes into a bridge, allowing the two sides to meet one another.

[30][31] The Fox network was initially resistant to this design, as executives were "really concerned that if the episodes didn't have ['over here'] Walter or Peter in them, it wouldn’t feel like our show anymore.

"[32] Historical idiosyncrasies were inserted into the parallel universe, such as a still-living John F. Kennedy, the non-existence of the FBI, and the Back to the Future franchise starring Eric Stoltz rather than Michael J.

Pinkner thought it allowed them to create and explore many "what-if" moments, such as if the September 11 attacks had occurred against the White House instead of the Twin Towers, or if the Statue of Liberty still possessed its shiny copper sheen.

[37] Many of the episodes involved the discovery and construction of a doomsday device, which Pinkner believed to be "a good thing to design a season around" because its mysteriousness was "a great story engine for us.

"[38] While the writers tried to maintain the concept of the "mythalone," a storyline that was attractive to both casual and devoted Fringe fans, the series became more invested in its mythology towards the end of the third season.

[41] The final three episodes of the season were "linked in one continuous story arc,"[42] and meant to seem like "you're turning the last page of a chapter in a novel.

[54] Other new and returning directors included Thomas Yatsko,[55] Jeffrey Hunt,[56] Kenneth Fink,[57] David Straiton,[58] Frederick E. O. Toye,[59] Chuck Russell,[60] and Charles Beeson;[61] they each directed one episode.

The parallel universe also featured Andre Royo as Henry Higgins, Amy Madigan as Marilyn Dunham, and Philip Winchester as Frank Stanton, all for three episodes.

The season featured single episodes with special guest appearances by Christopher Lloyd as Roscoe Joyce,[66] Jorge Garcia as Massive Dynamic security guard Kevin,[67] Paula Malcomson as Dana Gray,[68] Emily Meade as Ella Dunham,[69] Brad Dourif as Moreau,[70] and Leonard Nimoy as William Bell.

[73] At the beginning of the 2010–11 United States network television schedule, Fringe remained in its Thursday timeslot for the first nine episodes of the third season,[74][75] where it faced tough competition from the high-rated Grey's Anatomy and CSI: Crime Scene Investigation.

[78] Fox moved Fringe to a new Friday night timeslot on January 21, 2011,[75] where it typically broadcast opposite Supernatural, Dateline NBC, and CSI: NY.

[79][80] Because of the night's "death slot" status, this move made television critics and fans nervous that Fringe was near cancellation.

[87][88] Kevin Reilly, Fox's entertainment president, commented that "the series' ingenious producers, amazingly talented cast and crew, as well as some of the most passionate and loyal fans on the planet, made this fourth-season pickup possible.

According to a report released by Nielsen Company, Fringe was the only network television series among the top ten of most time-shifted shows of 2011.

Afraid, perhaps, to toy with viewers the way that Lost did, Fringe keeps the action moving, rapidly unspooling its mysteries, and that decision proves to be a wise one.

Rather than waiting for a future payoff, Fringe is cashing in with every episode, showing us the escalating war between worlds—and with likeable characters and compelling cases to boot.

"[94] In December 2010, the New York Times wrote Fringe "has kept its plates spinning entertainingly well into its third season" and called it "the best major-network show that no one is watching".

They noted, "With stellar performances, sci-fi intrigue and a newly introduced Doomsday machine in play that almost guarantees the two worlds will face off Thunderdome-style, this series just keeps getting better and better.

[113][114] In her 2011 book Into the Looking Glass: Exploring the Worlds of Fringe, author Sarah Clarke Stuart noted that the third season's "apocalyptic nature was fitting for an audience in the midst of such seemingly world-ending economic turmoil in 2010–2011."

To Clarke Stuart, Walter's remark in the episode "6B" that the world is tearing apart reflected "the sentiments of American viewers who were facing job loss and displacement at an unprecedented level.

Special features include two commentary tracks—"The Plateau" with Monica Owusu-Breen, Jeff Pinkner and Timothy Good, and "Lysergic Acid Diethylamide" with Jay Worth, Luyen Vu, and Tanya Swerling.