피아(彼我, Pia)는 대한민국의 록 밴드이다. 이름은 ‘너와 나’, ‘우주와 나’ 라는 뜻이다.

피아는 1998년, 부산에서 결성되어 부산의 라이브 클럽을 중심으로 활동하였으며 1999년, MBC에서 개최한 "제2회 MBC 록 페스티벌"에서 "기름덩어리"라는 곡으로 대상을 수상하며 주목받았다.

이후 서울로 상경해 《Pia@Arrogantempire.xxx》를 발매하여 데뷔하였다.

이후 록 페스티벌 등의 라이브를 중심으로 활동하다 2002년 말, 서태지컴퍼니 산하의 레이블 괴수 인디진에 합류하여 2003년 통산 2번째 앨범 《3rd Phase》를 발매하며 메이저에 진출하였다.

현재는 C9 엔터테인먼트로 소속사를 옮겨 활동 중이다.

Pia (피아) is a South Korean rock band formed in Busan in 1998. Meaning 'the Universe and I' or 'You and I' in Chinese characters (Pi:彼 A:我), Pia was originally formed by Hullang Lee (guitar), Kibum Kim (bass) and Yohan Ok (lead singer) who were later joined by Simz No (fx, keyboard) and, after several member changes on drums, Hye Seung Yang (drums). The band has maintained this line-up ever since their first official gig together, the 2001 Ssamzie Festival.

After touring in local clubs and rock festivals for a few years, they relocated to Seoul and released their debut album Pia@ArrogantEmpire.xxx in March 2001. Having gradually gained momentum, the band made a breakthrough at the 2002 ETP FEST and eventually signed to Goesoo Indegene, a major label established by Seo Taiji, one of Korea's most prominent musicians. After releasing three studio albums 3rd Phase (2003), Become Clear (2005), Waterfalls (2007) and an EP Urban Explorer (2008) through Goesoo, Pia left the label in 2009 and joined WinWon Entertainment in 2011, releasing their fifth studio album Pentagram that year.

While Pia originally began as a nu metal/hardcore[disambiguation needed] band recognized for their heavy guitar sound and Yohan's powerful screaming vocals, their musical style has changed significantly over the years. Having explored various genres such as alternative metal, emo core, garage rock, alternative rock, synthpop, and such, their current music is considered to be alternative rock and electronic rock. While their albums have generally become softer and more melodic with increasing electronic influences, Pia has consistently incorporated their original heavy and powerful sound to their evolving style.