Secret Agent Clank is an installment in the Ratchet & Clank series developed by High Impact Games and published by Sony Computer Entertainment. It was initially released in June 2008 for the PlayStation Portable, and later ported to the PlayStation 2 in May 2009 by Sanzaru Games. It is the second portable title in the series, the second developed by High Impact Games, and the first to feature Clank as the main character. It was also the last Ratchet & Clank game to be released for the PS2.

Clank dons his persona as Agent Clank from the in-universe fictional holovision Secret Agent Clank series, in which he works for a secret government organization simply known as the Agency. The game opens in Boltaire Museum, where Clank spies Ratchet stealing an Eye of Infinity from the museum. Believing that Ratchet must not be the perpetrator, Clank then begins a mission to prove Ratchet's innocence. Ratchet is locked up in a Prison Planet, among which many inmates include enemies he has fought on previous adventures, and must fight for survival. Meanwhile, Captain Qwark trails Clank, to claim credit for Clank's actions as Barney writes a biography on Qwark.

Secret Agent Clank allows the player to control Clank, Ratchet, and Qwark, with Clank as the main character playing his Secret Agent Clank alter ego. Clank's gameplay is a combination of the series' typical third person shooter and platformer gameplay as well as stealth elements. He has access to a wide variety of secret agent weapons disguised as real objects (such as the Tie-A-Rang, the Cufflink Bomb, and the Blowtorch Briefcase), and makes use of Jet Boots for platforming. Ratchet has access to many of his usual weapons, including several returning from Size Matters, while fighting enemies in prison. Qwark's gameplay varies depending on the section in particular, and normally involves him fighting enemies in outrageous scenarios during his own storytelling.

According to a Tweet by the Insomniac Games' Twitter account, Secret Agent Clank is a canon entry in the series, but its events are in-universe fiction. Secret Agent Clank was first described as an episode of the show in Tools of Destruction, though promotional material conflicted with the stance, claiming that Clank's role in the holo-vision shown is a cover for his covert life as an agent. Insomniac Games later affirmed the stance that Secret Agent Clank existed as an entry in the series. In-universe, Secret Agent Clank takes place in the same month as Size Matters.