Electronic Sound is the second studio album by the English rock musician George Harrison. Released in May 1969, it was the last of two LPs issued on the Beatles' short-lived Zapple record label, a subsidiary of Apple Records that specialised in the avant-garde. The album is an experimental work comprising two lengthy pieces performed on a Moog 3-series synthesizer. It was one of the first electronic music albums by a rock musician, made at a time when the Moog was usually played by dedicated exponents of the technology. Harrison subsequently introduced the Moog to the Beatles' sound, and the band featured synthesizer for the first time on their 1969 album Abbey Road.

Harrison began the project in Los Angeles, in November 1968, while he was producing sessions for his Apple Records artist Jackie Lomax. "No Time or Space" comprises an edit of a Moog demonstration given there by Bernie Krause, an American synthesizer exponent and Moog salesman. Once his own Moog system arrived in England, in February 1969, Harrison recorded the second piece, "Under the Mersey Wall", at his home in Surrey. Krause later said that, with "No Time or Space", Harrison recorded the studio demonstration without his knowledge and that it incorporated ideas he was due to include on his forthcoming album with Paul Beaver. The cover artwork of Electronic Sound was taken from a painting by Harrison. The front cover shows Krause operating the Moog console, while the back depicts Derek Taylor's office at Apple and the pressures afflicting the company at the time.

The album has received an unfavourable response from many rock critics; these writers dismiss it as unfocused, unstructured, and consisting of random sounds. Some commentators and musicians judge it to be an adventurous work that displays the Moog's sonic potential at a time when the system was in its infancy. In the United States and Canada, the LP was pressed with the two tracks swapped around, leading to confusion regarding the identity of the pieces. The order was corrected for the album's CD release in 1996. The 2014 reissue includes essays by Kevin Howlett and electronica musician Tom Rowlands, along with Dhani Harrison's explanation of his father's artwork.

Although a guitarist and, from 1966, an aspiring sitarist under Indian musician Ravi Shankar, George Harrison turned to keyboard instruments as a tool for songwriting in 1967. These instruments included Hammond organ on some of his songs with the Beatles, and Mellotron on several of the Western selections on his debut solo album, the Wonderwall Music film soundtrack. Described by producer George Martin as the most dedicated of the Beatles in finding and creating new sounds for the band's studio recordings, Harrison became intrigued by the potential of the Moog synthesizer while in Los Angeles in late 1968. He was introduced to the instrument by Bernie Krause, who, along with his Beaver & Krause partner Paul Beaver, was the Moog company's sales representative for the US West Coast.

An off-shoot of the Beatles' Apple record label, Zapple Records was intended as an outlet for avant-garde musical works and spoken-word albums. The music on Electronic Sound, consisting of two extended instrumental pieces – "Under the Mersey Wall" and "No Time or Space" – was performed on a Moog 3 modular system. Harrison bought the system from the Moog company through Krause, and later had it set up at EMI Studios in London for the Beatles to use on their recordings.

In author Alan Clayson's view, the album was Harrison's "gesture of artistic solidarity" towards John Lennon and Yoko Ono, whose experimental collaborations, having first appeared on the Beatles' 1968 track "Revolution 9", made up Zapple's other inaugural album, Life with the Lions. In a 1987 interview, Harrison said that Electronic Sound, like the Lennon–Ono album, was an example of Zapple's ethos of "let[ting] serendipity take hold" rather than a formal creative work.

All I did was get that very first Moog synthesizer, with the big patch unit and the keyboards that you could never tune, and I put a microphone into a tape machine … So whatever came out when I fiddled with the knobs went on tape – but some amazing sounds did happen.

According to the album's liner notes, "No Time or Space" was recorded "in California in November 1968 with the assistance of Bernie Krause". The title was a phrase Harrison had adopted when discussing the aim of Transcendental Meditation in a September 1967 interview for the BBC Radio 1 show Scene and Heard. Krause later said that "No Time or Space" was a recording of him demonstrating the Moog III to Harrison in Los Angeles, following a session for Jackie Lomax's album Is This What You Want?, which Harrison was producing at the time. Krause claimed that the demonstration was recorded without his knowledge and nor would he have given his consent, since his playing included ideas he intended to develop on the next Beaver & Krause album. Krause's name was originally included on the front cover of Electronic Sound, under Harrison's, but it was painted over at Krause's insistence. The words "Bernie Krause" were nevertheless visible under the silver ink on original LP pressings.