Shorey has signed a two-year contract with the Baggies, who have the option of a further year, and will face competition from Slovakia international Marek Cech and former England Under-21 defender Joe Mattock for the left-back spot.
"I'm delighted to welcome Nicky to the club," said West Brom boss Roberto Di Matteo.
"He's an experienced, solid, reliable left-back who likes to get forward and get involved.
"I also like the fact he's English and knows what the Premier League is all about.
"He's a player I've liked for some time.
"I've very much signed Nicky to compete for the left-back position and I have some good options down that flank as Marek can also play further forward.
"Nicky's arrival will not only increase competition but also means we will have options should we suffer injuries or suspensions."
Shorey, who has played in all four divisions of English football, started his career at Leyton Orient before in 2001 joining Reading, with whom he won promotion to the Premier League.
He joined Villa in 2008 but found first-team chances hard to come by and spent time on loan at Nottingham Forest and Fulham last term.
Shorey won two England caps under Steve McClaren in 2007 in friendlies against Brazil and Germany.