Jason Lee was meant to have a larger role in this film, but his screen time was rewritten shorter than planned due to scheduling conflicts with My Name Is Earl (2005). Most of his scenes were filled in with Zachary Levi's character, Toby Seville.
The Seville home has a house number of "1958". This is the year Ross Bagdasarian created the animated singing anthropomorphic chipmunks.
David Seville is a stage name of Ross Bagdasarian creator of the Chipmunks. He took the name "Seville" from the town in Spain, where he had once done military service.
It was originally scheduled to be premiered on March 19, 2010, but was moved up to a Christmas 2009 release instead.
The plot where Alvin, Simon, and Theodore meet Brittany, Jeanette, and Eleanor for the first time was reused from the first episode of Alvin & the Chipmunks (1983).