With 7,727 runs, Bell is the eighth-highest Test scorer in England’s history, but the 33-year-old has struggled for form of late and has scored only one Test century since July 2014.
Batsmen Nick Compton and Gary Ballance both earn recalls, but Adil Rashid drops out, leaving Moeen Ali and Samit Patel as England’s frontline spinners.
“Ian Bell has been an outstanding player for many years and undoubtedly still has plenty to offer England in the future,” national selector James Whitaker said in a statement on the ECB website.
“It was clearly a difficult decision, but he has struggled for runs in recent series and we felt that it was the right time for him to take a break and spend time working on his game out of the spotlight.”
Reacting on Twitter, Bell said: “I’m absolutely gutted not to be selected for the tour to South Africa.
“I certainly feel I could have contributed out there and have been working tirelessly to get into the best possible condition for the tour.
“I’m going to enjoy a winter break with my family for the first time in 11 years and come back determined to win my place back. Wishing all the guys selected the best of luck.”
England arrive in South Africa on December 11 and are due to play four Test matches, five one-day internationals and two Twenty20 internationals between late December and late February.
– Compton, Hales compete –
Fast bowlers Mark Wood and Steven Finn both miss out through injury, while Nottinghamshire batsman Alex Hales and Surrey left-arm fast bowler Mark Footitt are the only uncapped players in the squad.
Compton and Hales will compete for the right to open the batting with captain Alastair Cook after Ali failed to impress in the recent three-Test series with Pakistan in the United Arab Emirates, which England lost 2-0.
Middlesex batsman Compton scored two centuries in nine Tests before being dropped in 2013, while Yorkshire’s Ballance, who last featured in this year’s Ashes, has four centuries in 15 Tests.
“The inclusion of Nick Compton and Gary Ballance alongside Alex Hales, Joe Root and James Taylor gives (head coach) Trevor Bayliss and Alastair Cook plenty of options in the top order,” Whitaker added.
“Adil Rashid showed plenty of promise in the UAE, but with the conditions in South Africa making the likelihood of playing two spinners extremely remote, he misses out.
“We feel this provides an excellent opportunity for him to spend some time developing his white-ball skills in the lead-up to the ICC World T20 in March.”
Whitaker said it was “likely” that Adil will travel to Australia to play for a Big Bash franchise.
The first Test in Durban begins on Boxing Day, the second Test in Cape Town starts on January 2 and the two remaining matches will take place in Johannesburg (January 14-18) and Centurion (January 22-26).
England Test squad
Alastair Cook (capt), Moeen Ali, James Anderson, Jonathan Bairstow, Gary Ballance, Stuart Broad, Jos Buttler, Nick Compton, Mark Footitt, Alex Hales, Chris Jordan, Samit Patel, Joe Root, Ben Stokes, James Taylor, Chris Woakes