The only surprise in Andy Farrell's selection was the omission of Joey Carbery - Sexton's usual understudy at flyhalf - with his Munster teammate Jack Crowley and Leinster's Ross Byrne included.
Byrne, Ireland's forgotten man at 10 for much of Farrell's time in charge, kicked the winning penalty against Australia in November after being added to the squad at the last minute and has since performed well for Leinster.
Another in-form Leinster back, Jamie Osborne, is the only uncapped player selected. The 21-year-old, who can play at wing, centre and fullback, was player of the match in last weekend's European Champions Cup thrashing of Gloucester.
Leinster teammate Robbie Henshaw is Ireland's only major loss through injury as they look to build on their recent excellent form with a first Six Nations title in five years.
Sexton should also recover from a cheekbone injury in time for the trip to Cardiff, Leinster said last week.
"While there are a few players carrying knocks and others that have missed out on selection for the start of the tournament, they will have the opportunity to push their case playing for their provinces over the coming weeks," Farrell said.
Squad:
Backs: Bundee Aki (Connacht), Ross Byrne (Leinster), Craig Casey (Munster), Jack Crowley (Munster), Keith Earls (Munster), Jamison Gibson Park (Leinster), Mack Hansen (Connacht), Hugo Keenan (Leinster), Jordan Larmour (Leinster), James Lowe (Leinster), Stuart McCloskey (Ulster), Conor Murray (Munster), Jimmy O'Brien (Leinster), Jamie Osborne (Leinster), Garry Ringrose (Leinster), Johnny Sexton (Leinster), Jacob Stockdale (Ulster)
Forwards: Ryan Baird (Leinster), Finlay Bealham (Connacht), Tadhg Beirne (Munster), Jack Conan (Leinster), Gavin Coombes (Munster), Caelan Doris (Leinster), Tadhg Furlong (Leinster), Cian Healy (Leinster), Iain Henderson (Ulster), Rob Herring (Ulster), Ronan Kelleher (Leinster), Dave Kilcoyne (Munster), Joe McCarthy (Leinster), Peter O'Mahony (Munster), Tom O'Toole (Ulster), Andrew Porter (Leinster), Cian Prendergast (Connacht), James Ryan (Leinster), Dan Sheehan (Leinster), Josh van der Flier (Leinster)