Wright, who has also played for Arsenal and Everton, is expected to challenge Steve Simonsen for the Blades jersey.
Boss Gary Speed said: "We are delighted to be able to bring in someone of Richard's calibre. He has hundreds of first team games behind him."
Wright made his debut for the Tractor Boys in a 1-0 defeat against Manchester City at Maine Road in August 1996.
He has since gone on to clock up 457 career appearances at Ipswich, Arsenal, Everton, West Ham, Southampton (on loan) and two seasons back at Portman Road.
Wright made his England debut while still an Ipswich player in a 2-1 win in Malta in June 2000, winning his second cap in a 2-0 home defeat to Holland at White Hart Lane in August 2001, following his £6 million move to Arsenal.
Source: BBC Sport
Source: BBC Sport