Simon Alexander Neil (born 31 August 1979) is a Scottish musician, best known as the lead vocalist and guitarist for rock band Biffy Clyro.

Another side project fronted by Neil, Empire State Bastard, released their debut studio album Rivers of Heresy in September 2023, reaching number three in Scotland, forty six in the United Kingdom, number three on the UK Rock & Metal Albums Charts and sixty-nine in Germany.

[5] Born in Irvine, North Ayrshire, Scotland and grown up in Ayr, Neil formed a band in 1995 at 15 years old, recruiting Kilmarnock-based Ben Johnston and someone known only as Barry on drums and bass respectively, calling themselves Skrewfish.

[6] Barry was soon replaced by James Johnston, Ben's twin brother, and Biffy Clyro was effectively formed.

There is usually also a cloaked/masked figure on stage during performances, known only as "The Duke"; played by Sucioperro's ex-bassist Michael Logg (also known as "The Big Slice").

This character might be construed as the band's own version of Public Enemy's Flavor Flav or the Happy Mondays' Bez.

[10] Empire State Bastard is an extreme metal duo composed of Neil and ex-Oceansize frontman Mike Vennart.

The project has been described as "grindcore extreme metal" by Neil,[11] with Mike writing the songs and recording all guitars, and Simon focused on vocals and lyrics.