Steven Siro Vai (born June 6, 1960) is an American guitarist, songwriter, and producer who has sold over 15 million albums. After starting his career as a music transcriptionist for Frank Zappa, he recorded and toured in Zappa's band from 1980 to 1982. He began a solo career in 1983, and has released eight solo albums and won three Grammy Awards.

Vai has recorded and toured with Public Image Ltd., Alcatrazz, David Lee Roth, and Whitesnake. He has been a regular touring member of the G3 Concert Tour, which began in 1995. In 1999, he started his own record label, Favored Nations, intending to showcase "artists that have attained the highest performance level on their chosen instruments".