R. Daneel Olivaw is a fictional robot created by Isaac Asimov. The "R" initial in his name stands for "robot." He appears in the Asimov's Robot/Foundation Series, most notably in the novels The Caves of Steel, The Naked Sun, The Robots of Dawn, Robots and Empire, Prelude to Foundation and Foundation and Earth. He also appears in all of the books of the Second Foundation Trilogy.

Daneel is a robot built by Spacers from planet Aurora. Unlike many robots of the period, Daneel is constructed to be virtually indistinguishable from a human being (see: android). This "undercover" attribute enables him to help earth-policeman Elijah Baley solve crimes. Daneel and Baley first meet while Baley is investigating the murder of Roj Nemennuh Sarton, the human to whom Daneel is identical in appearance.

Daneel and Baley work together on a murder case on Spacer planet Solaria, as well as on the case of the "roboticide" of Daneel's "brother", Jander Panell. Also on Aurora, he first meets R. Giskard Reventlov, a robot with unique telepathic powers. Daneel invents the Zeroth Law of Robotics after both robots come to see the incompleteness of the existing Laws of Robotics. The Zeroth Law proves destructive to Giskard's positronic brain when he attempts to act upon it, as he violated the First Law in doing so and thus brought on a life-threatening "moral" conflict. Giskard bestows his abilities to Daneel, who over the course of 20,000 years adapts himself to be able to fully obey the Zeroth Law without the risk of shutdown.

For that time onward, Daneel manipulates the galaxy with the help of his many robot allies. He sets up both the Galactic Empire and Gaia in order to create a society that does not need robots. Under the guise of Eto Demerzel, he becomes the first minister to galactic Emperor Cleon I.

When Hari Seldon first comes to Trantor, R. Daneel Olivaw, under the guise of reporter Chetter Hummin (a play on word "human"), convinces Hari that the galactic empire is dying and that psychohistory must be developed into a practical science in order to save it. As Hummin, he convinces Seldon that Cleon's first minister Eto Demerzel is pursuing him and that it is imperative for Hari to escape and to try making psychohistory practical. He introduces Hari to Dors Venabili, who becomes Hari's friend, protector, and future wife. At the end of Seldon's "Flight" it is revealed that Hummin and Demerzel are actually the same person, and are both false identities of R. Daneel Olivaw. Demerzel appears again briefly in the epilogue to Forward the Foundation, which says he was one of the few in attendance at Hari Seldon's funeral.

R. Daneel Olivaw appears once more in Foundation and Earth, where Golan Trevize and Janov Pelorat from the Foundation eventually find the radioactive Earth, and Daneel's base on the moon, and learn about his paternalistic manipulations, including causing of the settlement of Alpha Centauri, the creation of Gaia, and psychohistory. Ultimately, Daneel convinces Trevize that the creation of Galaxia is the correct choice.

Isaac Asimov said that the reason Daneel appeared so often in his books was that his readers and publishers begged it of him.