The fourth and final season of The O.C., an American teen drama television series, aired in the United States from November 2, 2006, to February 22, 2007, and consisted of 16 episodes. The O.C's final season aired Thursdays at 9:00 p.m. ET in the United States on Fox, a terrestrial television network. Fox tested a new timeslot by airing the second episode on Wednesday at 9:00 p.m. ET against ABC's Lost and CBS's Criminal Minds. With Lost about to enter a three-month hiatus, Fox hoped that changing the timeslot for The O.C. would attract back viewers it had lost since the end of the previous season; however, the move was unsuccessful and the show returned to its Thursday timeslot.

The season was released on DVD as a five-disc boxed set under the title The O.C.: The Complete Fourth Season on May 22, 2007, by Warner Bros. Home Video. The season was also made available in the American versions of Zune and iTunes Store. Before the season premiered on television, it was available through on demand streaming. In the US, streaming was available from October 26, 2006, at 3:01 a.m. ET onwards, through Fox Interactive Media's MySpace and MyFoxLocal stations.

In Canada, the fourth season was simulcast on the terrestrial CTV Television Network. Additionally, as a result of an agreement between Warner Bros. and CTV, the first episode was available to be streamed from October 30, 2006, at 12:00 p.m. ET onwards, through the CTV Broadband Network. In the United Kingdom the season premiered on January 9, 2007, on E4, and in Australia it was broadcast by Network Ten on November 7, 2006, at 8:30 p.m. (local time).

Synopsis

Life after high school hasn't been great for the graduates of Harbor high. Ryan, Julie, and Summer have trouble adjusting to life without Marissa. Taylor ran into some trouble. Back in Newport for her Junior year, Kaitlin begins to act out. Sandy and Kirsten face another bombshell life puts in their lap or oven. Seth tries to find his calling. Ryan gets an unexpected visitor who helps Julie out of her grief.

Cast and characters

Episodes

No. overall	No. in season	Title	Directed by	Written by	Original air date	Prod. code	U.S. viewers (millions)
77	1	"The Avengers"	Ian Toynton	Josh Schwartz & Stephanie Savage	November 2, 2006 (2006-11-02)	3T5251	3.39
Nearly 6 months has passed, Marissa's friends and family has trouble adjusting to life without her. Meanwhile, Taylor has convinced everyone she's in France.
78	2	"The Gringos"	Patrick Norris	John Stephens	November 7, 2006 (2006-11-07)	3T5252	3.54
Ryan and Seth take a trip down to Mexico to find Volchok. Taylor confesses why she's not in France. Kaitlin's reckless behavior results in Julie volunteering at Harbor's clothing drive.
79	3	"The Cold Turkey"	Michael Lange	J. J. Philbin	November 9, 2006 (2006-11-09)	3T5253	3.73
Volchok turns to Sandy for advice without Ryan's knowledge. Summer prepares to face life in Newport as she returns from Brown. Meanwhile, Julie finds herself alone on Thanksgiving when she is not welcome in the Cohens' house.
80	4	"The Metamorphosis"	Norman Buckley	Leila Gerstein	November 16, 2006 (2006-11-16)	3T5254	3.77
Summer realizes her new personality is just a new way of coping with Marissa's death, and Seth continues to support her. Ryan helps Taylor legalize her divorce. Meanwhile, Julie and Kaitlin attempt to stay out of trouble.
81	5	"The Sleeping Beauty"	Ian Toynton	John Stephens	November 30, 2006 (2006-11-30)	3T5255	3.67
Taylor finds a new way to get closer to Ryan but ends up turning to Kaitlin for support. Summer and Che take their activism to a new level, but suffer severely. Meanwhile, Julie fights for the affection of Kaitlin's new tennis instructor, and Kirsten seeks additional funding for NewMatch.
82	6	"The Summer Bummer"	Michael Lange	Josh Schwartz & Stephanie Savage	December 7, 2006 (2006-12-07)	3T5256	3.82
Seth visit Summer at Brown but runs into Che. Sandy and Kirsten try to find an opportunity to bond with Ryan. Kaitlin attempts to gain Harbor recognition by throwing a party. Meanwhile, Julie learns NewMatch is no longer just a dating service.
83	7	"The Chrismukk-huh?"	Ian Toynton	J. J. Philbin & John Stephens	December 14, 2006 (2006-12-14)	3T5257	4.25
Ryan and Taylor fall off a ladder and end up in the hospital. Taylor confronts Veronica about her attitude. Meanwhile, a letter from Marissa is sent to the Cohen house.
84	8	"The Earth Girls Are Easy"	Norman Buckley	Mark Fish	December 21, 2006 (2006-12-21)	3T5258	4.15
Ryan plans a surprise trip for Taylor, but Seth comes along and brings Summer, whose future is at stake. Meanwhile, Bullit gets an old friend to take care of Julie's accounting, much to her displeasure and Sandy's suspicion.
85	9	"The My Two Dads"	Michael Schultz	Josh Schwartz & Stephanie Savage	January 4, 2007 (2007-01-04)	3T5259	3.93
Kaitlin fails a class presentation and is forced to work with a smart classmate, whom she ends up liking. Seth and Summer move forward with their plans, regardless of how they really feel. Sandy confronts Frank about why he's in Newport.
86	10	"The French Connection"	John Stephens	J. J. Philbin	January 11, 2007 (2007-01-11)	3T5260	3.83
Ryan learns about Taylor's summer in France. Seth seeks Dr. Roberts' permission to marry Summer. Kaitlin realizes she likes Will. Summer reconnects with Holly and worries about her future. Meanwhile, Kirsten makes a shocking discovery at NewMatch.
87	11	"The Dream Lover"	Patrick Norris	Leila Gerstein	January 18, 2007 (2007-01-18)	3T5261	3.96
Che brings Seth on a trip to the forest. Taylor decides she should no longer see Ryan. Julie begs for Kirsten's reconciliation. Kaitlin shuts Will out of her life.
88	12	"The Groundhog Day"	Ian Toynton	Mark Fish	January 25, 2007 (2007-01-25)	3T5262	3.57
Ryan tries to act like he doesn't miss Taylor, who is seeing a therapist. Kirsten's turning 40 but has her mind focused on other things. Julie is having an affair that Kaitlin does all she can to stop. Che makes a discovery about Seth.
89	13	"The Case of the Franks"	Norman Buckley	J. J. Philbin	February 1, 2007 (2007-02-01)	3T5263	3.82
Ryan and Taylor devise a plan to bring Julie and Frank closer, but Kaitlin tries to keep Bullit in Julie's personal life. Summer begins to have doubts in her relationship with Seth. Kirsten opens up about her past with Jimmy to Sandy as they prepare for their new baby.
90	14	"The Shake Up"	Ian Toynton	John Stephens	February 8, 2007 (2007-02-08)	3T5264	3.58
Kaitlin does all she can to sabotage Julie and Frank's relationship. Ryan and Taylor tell each other how they feel. Summer encourages Seth to find something he's passionate about. Kirsten realizes what Newport's society is all about. As the night comes to a close, an earthquake hits Newport Beach.
91	15	"The Night Moves"	Patrick Norris	Stephanie Savage	February 15, 2007 (2007-02-15)	3T5265	3.65
After the earthquake, Ryan tells Seth he needs to get to the hospital, but doesn't want to worry Taylor. An aftershock leaves Kirsten wondering if her unborn baby is still alive. Taylor takes control when she and Summer hear an intruder in their home. Kaitlin and Julie are trapped in an ice cream store.
92	16	"The End's Not Near, It's Here"	Ian Toynton	Josh Schwartz	February 22, 2007 (2007-02-22)	3T5266	6.59
Ever since the earthquake destroyed their home, the Cohens have taken temporary residence at the Roberts' home. Sandy and Kirsten search for a new home. Summer must choose between touring with GEORGE and her future with Seth. Taylor and Ryan determine their future together. Julie must decide whether to marry Frank or Bullit. Before Ryan leaves Newport, as he turns out of the driveway, he remembers the first time he met Marissa. Years later, Ryan is attending Berkeley. Julie graduates from college with Kaitlin, Frank, Bullit and her son applauding her achievement. Sandy is now teaching law classes. Seth and Summer get married, with Ryan and Taylor as their best man and maid of honor and Sophie Rose Cohen as their flower girl. Ryan, as an architect, reaches out to a young boy, much in the way Sandy reached out to him years ago.