Gurney said that the play had been rejected by many producers before the Manhattan Theatre Club produced it, because "it equated a dog with a woman, and to ask a woman to play a dog was not just misogynist, but blatantly sexist." Gurney added that he did not think that way. He noted that the play has a "timely message of the need to connect in an increasingly alien and impersonal world. 'There is a need to connect, not only to a dog, but to other people through the dog.'"
In an article for the 2nd Story Theatre in Warren, Rhode Island, Eileen Warburton wrote that "'Sylvia' is a love story, of course, or at least a story about a man’s relationship with one of those magical animals people in stories so often meet just when they’re at a troubling crossroads in life, an animal that is a guide to finding the best in ourselves.... our propensity to project human characteristics and motives onto our non-human companions is dramatized by having the adopted dog played by a sexy, adoring young woman."
Sylvia opened Off-Broadway at Stage I of the Manhattan Theatre Club on May 2, 1995, where it ran for 167 performances. Directed by John Tillinger, the cast included Sarah Jessica Parker as "Sylvia", Blythe Danner, and Charles Kimbrough. The production received Drama Desk Award nominations for Outstanding Play, Outstanding Actress in a Play (Parker), and Outstanding Costume Design (Jane Greenwood).
The play was produced by the Berkshire Theatre Group, Stockbridge, Massachusetts, in July 2011. The reviewer called it a "comic masterpiece".
The play's first Broadway production began previews at the Cort Theatre on October 2, 2015, starring Annaleigh Ashford as "Sylvia", Matthew Broderick, Julie White and Robert Sella, directed by Daniel J. Sullivan. The production officially opened on October 27, 2015 and will run a limited engagement through January 24, 2016. Costumes are designed by Ann Roth. The Broadway production has announced that it is closing three weeks early, due to poor reviews and ticket sales. 
The place is New York City, the time is the 1990s.
Middle-aged, upper-middle class Greg finds Sylvia, a dog (played by a human), in the park and takes a liking to her. He brings her back to the empty nest he shares with Kate. When Kate gets home, she reacts very negatively to Sylvia and wants her gone. They eventually decide that Sylvia will stay for a few days before they decide whether she can stay longer, but Greg and Sylvia have already bonded. Over the next few days, Greg spends more and more time with Sylvia and less time at his job. Greg and Sylvia go on long walks; they discuss life and astronomy. Already dissatisfied with his job, Greg now has another reason to avoid work.
Tension increases between Greg and Kate, who still does not like Sylvia. Eventually, Greg becomes completely obsessed with Sylvia, and Kate fears their marriage is falling apart. Kate and Sylvia are at odds with each other, each committed to seeing the other defeated. Greg meets a strange character at the dog run, who gives Greg tips on how to manage Sylvia and his predicament involving Kate. Greg has Sylvia spayed. Sylvia is angry and in pain, but she still loves him completely.
Kate's friend pays a visit and is repulsed by Greg and Sylvia. Greg, Kate and Sylvia sing "Every Time We Say Goodbye".
Greg and Kate visit a therapist, Leslie, who is ambiguously male and female depending on her patients' state of mind. After a session with Greg, Leslie tells Kate to get a gun and shoot Sylvia: "I hope you get her right between the eyes."
Kate is asked to teach abroad, in London, and tells Greg that the English have a six-month quarantine for any dogs coming into the country. Greg is unwilling, but eventually he succumbs and gives the news to Sylvia, that he must give her away, to a family who have a farm in Westchester County. Greg and Sylvia have a heated and tender moment. Kate and Sylvia say goodbye; but, before Greg and Sylvia leave for Westchester, Sylvia returns the annotated and slightly chewed version of "Alls Well That Ends Well" that Kate has been looking for, and Kate has a change of heart.
The last scene is directed toward the audience. Sylvia has died, and Greg and Kate still hold her memory in all fondness.
Vincent Canby, in his review in The New York Times of the original 1995 production wrote "Dramatic literature is stuffed with memorable love scenes. But none is as immediately delicious and dizzy as the one that begins the redeeming affair in A. R. Gurney's new comedy, 'Sylvia,'... Here's a romantic triangle about Greg (Charles Kimbrough), Kate (Blythe Danner) and the mongrel named Sylvia (Sarah Jessica Parker) who, as Kate puts it, eats a serious hole in their 22-year marriage."
The CurtainUp reviewer of a 2010 regional production called the play "a delightful fantasy, but also a psychologically persuasive look at one man's mid-life crisis."
The USA Today reviewer of the 2015 Broadway production praised the performers, writing: "Kate, played by a wonderfully wry Julie White... Broderick is very much in his comfort zone playing the blithely goofy straight man... Ashford has the juiciest role, ... and she plays it to hilt, without letting Sylvia chew the scenery (or Kate's red heels) entirely. The actress is a riot sliding on knee pads, wagging her legs around and rushing down the aisle to suggest hot pursuit of a male canine.... directed with a winking eye and a buoyant heart."
The Newsday reviewer wrote of a "sympathy-evoking Julie White", the "utmost clueless sweetness by Mathew Broderick in his most engaged and endearing performance in a long time", and the "spectacular Annaleigh Ashford", but criticized the direction: "...increasingly annoying directorial exaggeration as Daniel Sullivan's production progresses..."
- Pacheco, Patrick. "On the Road With A.R. Gurney's 'Sylvia'" playbill.com, January 22, 1997
- Warburton, Eileen. "And They Called it Puppy Love" 2ndstorytheatre.com, April 30, 2014
- "Drama Desk Awards" dramadesk.org, accessed May 28, 2015
- Ng, David. "Isn't that 'Sylvia' just too cute?" Los Angeles Times, November 5, 2007
- Murray. Larry. Review: “Sylvia” is the doggone funniest play of the season" berkshireonstage.com, July 17, 2011
- Gans, Andrew and Viagas, Robert. "Matthew Broderick Will Return to Broadway This Fall" playbill.com, July 28, 2015
- Viagas, Robert. "Something to Bark About: Two 2015 Tony Nominees to Star in Broadway Bow of 'Sylvia' " playbill.com, May 28, 2015
- Staff. "The Verdict: Critics Review 'Sylvia' Starring Annaleigh Ashford and Matthew Broderick" Playbill, October 27, 2015
- Lloyd Webber, Immogen "Sylvia, Starring Tony Winners Matthew Broderick & Annaleigh Ashford, to Close Early on Broadway" broadway.com, November 24, 2015
- Canby, Vincent. "Theater Review. 'Sylvia'; Gurney's Notion Of a Very Different Menage a Trois" The New York Times, May 24, 1995
- Saltzman, Simon. "A CurtainUp New Jersey Review. 'Sylvia' " curtainup.com, April 2, 2010
- Gardner, Elysa. "It's puppy love for doggone adorable 'Sylvia' on Broadway USA Today, October 27, 2015
- Winer, Linda. "'Sylvia' review" Newsday, October 27, 2015