Elijah Baley is a fictional character in Isaac Asimov's Robot series. He is a plainclothesman, a homicide detective on the New York City police force. Although Asimov's novels do not mention specific birth and death dates, they can be determined by close reading and inference: Elijah was born in 4679 and died in 4762 . His wife, Jezebel Baley, prefers to be called Jessie. Their son, Bentley, became a leader in the second wave of interplanetary space exploration. The planet Baleyworld is named in Bentley's honor.

He is the main character of The Caves of Steel, The Naked Sun, The Robots of Dawn, and the short story "Mirror Image". He is talked about heavily in Robots and Empire, which is set roughly two hundred years after his death.

Asimov's novels are typically devoid of profanity. Consequently, Baley's favourite expletive is "Jehoshaphat!" which he says in times of great stress or excitement.

In the 1964 British television adaptation of The Caves of Steel, Baley was played by Peter Cushing.

In The Caves of Steel, he is called to help solve the murder of a Spacer. The Spacers assign to him a robot partner, R. Daneel Olivaw, with whom he becomes a life-long friend. Later, in the Robots of Dawn, he realizes R. Giskard's telepathic abilities long before anyone else does. Giskard modifies Baley's mind to prevent him from being able to tell anyone.