ELO 2 is the second studio album by the Electric Light Orchestra (ELO), released in 1973. In the US, the album was released as Electric Light Orchestra II. It was the band's last album to be released by the Harvest label, the last (in the UK) on which the band used the definite article The in their name, and the one that introduced their abbreviated name 'ELO'.

The album was originally to be titled The Lost Planet, but that concept was quietly dropped. During the initial recording sessions, Roy Wood left the band and formed Wizzard in June 1972, taking Bill Hunt and touring cellist Hugh McDowell with him. Although uncredited at the time, Wood performed on two tracks, playing cello and bass on "In Old England Town" and "From the Sun to the World". Classically trained cellist Colin Walker replaced Wood, and Wilfred Gibson played violin. Richard Tandy made his ELO studio debut on this album, playing keyboards; he had earlier performed live with the original lineup alongside Wood, Gibson, co-frontman Jeff Lynne, drummer Bev Bevan and cellist Mike Edwards, playing bass (and in TV appearances with the Move playing guitar). Bassist and vocalist Mike de Albuquerque also made his ELO studio debut on the album. All five pieces are longer than standard rock songs, and feature multi-layered orchestral instruments that create a dense, complex sound.

ELO 2 received mixed reviews from critics. AllMusic`s Bruce Eder says "the album holds up well, and it and the single did go a long way toward getting them the beginnings of an audience in America." The Daily Vault says "After hearing ELO II, not only would some of these rock fans take another look at ELO's music in another sense, they just might do the same for Classical Music as well."

Harvest released ELO 2 in March 1973. Along with its predecessor, ELO 2 is the least commercial-sounding album the band released, although it reached the British Top 40 album chart, whereas its more concise follow-up, On the Third Day, did not.

One song from the album was released as a single, their cover of Chuck Berry`s "Roll Over Beethoven". The edit of that song (4:32) was a top 10 hit in Britain, and also received radio airplay in America. The song is also a concert staple.

The British and American sleeves differed, as did the title; in the UK it was released in a gatefold sleeve titled ELO 2 with a painting of a light bulb travelling through space with the wording 'ELO2' on the base of the bulb, while in the US the cover featured a more ornate light bulb against a night sky and was titled Electric Light Orchestra II. For reasons unknown, "Roll Over Beethoven" was slightly edited in length compared with its US counterpart. Track 2 "Momma" was Americanized to "Mama" for the US release. An instrumental version of "In Old England Town", the opening track, became the B-side to the single "Showdown". The album contains the band's longest track, the anti-war song "Kuiama".

In 2006 the album was remastered and expanded in the US, with a slightly different running order to the UK 2003 EMI version, with both versions sharing the same Hipgnosis album art for the first time.

All tracks are written by Jeff Lynne, unless otherwise noted.