The show was green-lit by CBS who were interested in working with Sarah Michelle Gellar. They failed to pick up to the pilot to a full series citing that it was down to a lack of available spots on the schedule and the serialization of the show not fitting in with CBS's procedural nature. However, the show was immediately picked up by the CW network thereafter.
The pilot was filmed in New York City but subsequent episodes were filmed in Los Angeles.
Costars Sarah Michelle Gellar and Kristoffer Polaha have both played members of the Kennedy family in television movies: Gellar played the teenage Jacqueline Bouvier in the 1991 miniseries A Woman Named Jackie, and Polaha played Bouvier's son John F. Kennedy Jr. in 2003's America's Prince: The John F. Kennedy Jr. Story (2003) (TV).
Caitlin Custer was originally cast as Juliet Martin but was replaced by Zoey Deutch when the series was picked up. Juliet's scenes were re-shot upon Deutch's casting.
There are several possible meanings for the show's title. The most straightforward definition is "something that strongly resembles a second thing;" there have been at least two other filmed thrillers about twins that also used this meaning of "ringer" in their titles (1988's Dead Ringers starring Jeremy Irons twice, and 1964's Dead Ringer starring Bette Davis twice). A "ringer" can also be a synonym for an impostor or someone posing as someone else, just as Bridget pretends to be Siobhan. The third reference that the show's title makes is to the homophone "wringer," which can mean a difficult or painful situation.
Friends of Siobhan often shorten her name to "Siobh" (pronounced "Shiv"). This is also a slang term for a makeshift blade or weapon used in prison.
Different hairstyles are used to help the audience distinguish which twin Sarah Michelle Gellar is portraying (Siobhan or Bridget). Siobhan wears her hair up in a bun, braided or pulled back whereas Bridget wears hers down.
On May 11th, 2012, The CW Network announced the cancellation of Ringer due to low ratings. Fans of the series did their best to keep it on air by having online petitions on such sites as Twitter.com, Ipetitions.com and Gopetition.com. On Petetionbuzz.com the series gained well over 10,000 signatures in just a couple of weeks. The petition states how Ringer has been nominated for 12 awards throughout its run and is airing in more than 40 countries worldwide and doing well internationally. The petition also points out how fans would be happy to see the show on TV again, even if it were not on The CW. Suggested networks included TNT, AMC, or FX.