Replicas is the second and final studio album by the English new wave band Tubeway Army, released on 6 April 1979 by Beggars Banquet Records. It followed their self-titled debut from the previous year. After this, Tubeway Army frontman Gary Numan would continue to release records under his own name, though the musicians in Tubeway Army would continue to work with him for some time. Replicas was the first album of what Numan later termed the "machine" phase of his career, preceding The Pleasure Principle (1979) and Telekon (1980), a collection linked by common themes of a dystopian science fiction future and transmutation of man/machine, coupled with an androgynous image and a synthetic rock sound.

Fuelled by a surprise No. 1 hit single, "Are 'Friends' Electric?", the album also reached No. 1 in the UK charts in July 1979 and was certified Gold by the BPI for sales in excess of 100,000 copies.

A loose concept album, Replicas was based on a dystopian book Numan hoped to eventually complete, set in a not-too-distant future metropolis where Machmen (androids with cloned human skin) and other machines keep the general public cowed on orders from the Grey Men (shadowy officials). While the album's setting and lyrics were directly inspired by the science fiction of Philip K. Dick, particularly his seminal work Do Androids Dream of Electric Sheep?, the title was not. Although Numan's Machmen were similar to replicants, the term used for androids in Ridley Scott's Blade Runner (based on Dick's book), Scott's film came out three years after Tubeway Army's album and Dick never used the word replicant in his original 1968 novel. The album cover shows Numan as a Machman staring out from his room at a waning crescent moon hovering above "The Park" as a barely visible man stands outside while Numan's reflection stares back at himself. The picture was also used for the cover of "Down in the Park", the first single from the album.

Replicas was recorded in late 1978 at Gooseberry Studios, London and completed in February 1979 with overdubs and remixing at Marcus Music Studios.

Musically, Numan's main influence was the commercially unsuccessful John Foxx-led incarnation of Ultravox. Tracks like "Speed of Life" and "Breaking Glass" from David Bowie's Low were also cited, along with Kraftwerk's The Man-Machine album, in particular the long and wistful track "Neon Lights".

The recording built upon the sound of the first Tubeway Army album. While the tracks "The Machman", "You Are in My Vision" and "It Must Have Been Years" recalled the earlier album's guitar-oriented rock, the rest were built solidly around an analog synthesizer, the Minimoog. Along with "Are 'Friends' Electric?", this included "Me! I Disconnect from You", the atmospheric "Down in the Park" (released as a single prior to the album and acquiring cult status though not commercial success), the multi-layered title track and the closing instrumentals "When the Machines Rock" and "I Nearly Married a Human", the latter featuring Numan's first use of a primitive drum machine; it appeared the following year in Carl Sagan's TV series Cosmos: A Personal Voyage.

Smash Hits reviewer Red Starr found the album to have "Strong futuristic imagery, simple but catchy melodies and riffs, haunting synthesiser work — all strikingly delivered in distinctive fashion. Intriguing and definitely different — a good one."

The New York Times deemed the album "weird synthesizer effects and fashionably adenoidal songs and vocals over an accessibly rocking rhythm section."