Thursday's match at Lord's will be Joe Root's first since succeeding Alastair Cook as captain and his Yorkshire team-mate Ballance, who is the second highest scorer in the Specsavers County Championship with 815 runs, will slot in at number three.
The left-hander looked to be in for a lengthy international exile after making just 24 runs in four torturous innings in Bangladesh in October but his weight of runs this summer have persuaded the selectors to overlook Surrey opener Mark Stoneman and Middlesex batsman Dawid Malan, who had also been considered.
Middlesex seamer Roland-Jones is also named in the 12-man squad for his home ground, with fellow seamers Chris Woakes and Jake Ball ruled out, while Hampshire's slow left-armer Dawson is retained ahead of Adil Rashid after making his debut in Chennai in Cook's curtain call.
While Ballance has flourished this season, Lancashire's Haseeb Hameed - who won glowing reviews for his performances in India over the winter - has been in dreadful form and misses out. Durham's Keaton Jennings, who scored a century on debut in the Mumbai Test, will open with Cook against the country of his birth.
In the bowling ranks, Stuart Broad has been passed fit after a troublesome foot problem and will line-up for Nottinghamshire in the Royal London One-Day Cup final on Saturday and Mark Wood makes a welcome return for the first time since October 2015, having overcome a catalogue of injury problems.
National selector, James Whitaker, said: "There is great excitement around the first Test of the summer and with the start of a new era under the captaincy of Joe Root this is an exciting time for English cricket.
"Yorkshire's Gary Ballance could play his first Test since October. He has been in fantastic touch with the bat in the Championship averaging over 100. He deserves to be included and we feel that he will add maturity and experience to our middle-order.
"Toby Roland-Jones is a player we have been monitoring for quite some time and deserves his chance after a strong couple of seasons with Middlesex in red ball cricket. He came close last year when he was named in the Test squad against Pakistan in July. Toby has been in good form this campaign and his ability to seam the ball along with the fact that he can score useful runs down the order gives us a number of options.
"On behalf of the selectors, I would like to wish Joe Root, Trevor Bayliss and all the squad the very best for what will be a competitive series against South Africa."
England squad
J Root (Yorkshire, captain), A Cook (Essex), K Jennings (Durham), G Ballance (Yorkshire), B Stokes (Durham), J Bairstow (Yorkshire), M Ali (Worcestershire), L Dawson (Hampshire), S Broad (Nottinghamshire), T Roland-Jones (Middlesex), M Wood (Durham), J Anderson (Lancashire).
