"The Secret Origin of Felicity Smoak" is the fifth episode of the third season, and fifty-first overall episode, of the American television series Arrow, originally broadcast on The CW. Based on the DC Comics character Green Arrow, the series follows the story of billionaire vigilante Oliver Queen, portrayed by Canadian actor Stephen Amell, who returns home after five years supposedly stranded on a Pacific island, featuring flashback sequences to his time away. The series is part of the Arrowverse franchise, alongside spin-off shows The Flash, Legends of Tomorrow, Supergirl, Batwoman and other associated media. This episode is notable as the first Arrow episode to feature flashback sequences centered entirely on a character other than Oliver Queen, focusing instead on the backstory of the character Felicity Smoak, played by Emily Bett Rickards. The episode was written by Ben Sokolowski and Brian Ford Sullivan and directed by Michael Schultz. It premiered in the United States on The CW on November 5, 2014.

The episode flashbacks to the late 2000s, exploring Felicity's time as a rebellious goth and student at MIT alongside her then-boyfriend Cooper Seldon, portrayed by Nolan Gerard Funk, which has repercussions for her in the present day. It also features the first appearance of Charlotte Ross as Felicity's mother Donna Smoak and ends with the apparent revelation of the murderer of the character Sara Lance. The episode stars Stephen Amell as Oliver Queen alongside Emily Bett Rickards as Felicity Smoak with Katie Cassidy as Laurel Lance, David Ramsey as John Diggle, Willa Holland as Thea Queen, Colton Haynes as Roy Harper, John Barrowman as Malcolm Merlyn and Paul Blackthorne as Quentin Lance. Season three recurring stars Brandon Routh as Ray Palmer and J. R. Ramirez as Ted Grant also feature in the episode.

The episode was watched live by 2.73 million viewers on its first broadcast, achieving the fourth-highest ratings share of the show's third season. It was generally well received with critics' praising the performances of Rickards and Ross and the character development in the episode, but criticizing the more predictable elements of the plot. The episode holds a critics' approval rating of 100% on review aggregator site Rotten Tomatoes.

In the late 2000s, Felicity Smoak is a student at the Massachusetts Institute of Technology (MIT). Styling herself as a dark-haired goth, she considers herself to be a hacktivist, alongside her then boyfriend Cooper Seldon and his roommate Myron Forrest. Felicity creates a computer virus that enables the trio to access government mainframes, but objects to Cooper's plan to wipe all records of student loans from the system. However, his attempt is tracked by the Federal Bureau of Investigation and he is arrested and later sentenced to jail. Following Cooper's apparent suicide, Felicity is shown to have changed her image, dying her hair blonde, and abandoning her goth style wardrobe.

Five years later, Felicity discovers that cyber-attacks by a group calling themselves 'Brother Eye' have been launched using the code she developed whilst at MIT. Felicity and her mother, Donna, are kidnapped by the group, revealed to be led by an alive and well Cooper, who admits his suicide was faked by the National Security Agency. Felicity agrees to help him hack into the Treasury Department when he threatens to hurt Donna, but manages to secretly contact Oliver Queen, who aids in rescuing the pair. The episode ends with Roy Harper waking from a nightmare in which he sees himself shooting Sara Lance, making him wonder if he is in fact her killer.

Arrow was developed for television by Greg Berlanti, Andrew Kreisberg and Marc Guggenheim in 2012, and premiered on The CW in October of the same year. The series is loosely based on the DC Comics character Green Arrow, and would go on to be the progenitor of a franchise of television shows and other associated media based around adaptations of a variety of DC Comics characters, set within a shared universe, collectively known as the 'Arrowverse'.

Loosely based on the DC Comics character of the same name, Felicity Smoak was originally written as a one-off guest star for the first season Arrow episode, "Lone Gunmen". The success of the character led to actress Emily Bett Rickards being promoted to recurring status throughout season one and to the main cast from season two onwards. In 2014, during Arrow's second season, executive producer Marc Guggenheim discussed ways in which the writing staff had worked to develop a deeper back story for the character, promising that more of this would be seen on screen in both seasons two and three.

Interviewed at the San Diego Comic-Con Arrow panel in 2014, executive producer Andrew Kreisberg confirmed that the third season of the show would contain an episode centered around the character, exploring her history in more depth. He also stated that the episode would be entitled "Oracle", a nod to the DC Comics character of the same name. However, in an interview given in August of the same year Guggenheim revealed that the title had been changed to "The Secret Origin of Felicity Smoak".