Sexton missed the Round 3 fixture in Rome against Italy having picked up a knock against France in the previous round. Sexton is currently seven points behind the all-time leading Six Nations points scorer, fellow Irishman Ronan O’Gara (557 Six Nations points).
Conor Murray is also restored to the starting line up having impressed off the bench against Italy. In the midfield, Bundee Aki shifts to inside centre with Garry Ringrose returning to the starting line-up.
The back three that has started every game of this Championship campaign lines out again with Hugo Keenan at full-back and Mack Hansen and James Lowe on the wings.
Up front, Dan Sheehan and Tadhg Furlong are introduced to the front row to join Andrew Porter.
James Ryan and Iain Henderson lock down at second row with Peter O’Mahony starting at blindside flanker, Caelan Doris shifting to number eight and Josh van der Flier lining out at openside.
Cian Healy, Jamison Gibson-Park and Robbie Henshaw are included amongst the replacements alongside Ronan Kelleher, Tom O’Toole, Ryan Baird, Jack Conan and Ross Byrne.
Ireland (v Scotland):
15. Hugo Keenan (Leinster/UCD) 28 caps
14. Mack Hansen (Connacht/Corinthians) 12 caps
13. Garry Ringrose (Leinster/UCD) 49 caps
12. Bundee Aki (Connacht/Galwegians) 44 caps
11. James Lowe (Leinster) 18 caps
10. Johnny Sexton (Leinster/St Mary’s College) 111 caps (c)
9. Conor Murray (Munster/Garryowen) 103 caps
1. Andrew Porter (Leinster/UCD) 51 caps
2. Dan Sheehan (Leinster/Lansdowne) 15 caps
3. Tadhg Furlong (Leinster/Clontarf) 63 caps
4. Iain Henderson (Ulster/Academy) 71 caps
5. James Ryan (Leinster/UCD) 51 caps
6. Peter O’Mahony (Munster/Cork Constitution) 92 caps
7. Josh van der Flier (Leinster/UCD) 48 caps
8. Caelan Doris (Leinster/St Mary’s College) 26 caps
16. Ronan Kelleher (Leinster/Lansdowne) 20 caps
17. Cian Healy (Leinster/Clontarf) 121 caps
18. Tom O’Toole (Ulster/Ballynahinch) 7 caps
19. Ryan Baird (Leinster/Dublin University) 9 caps
20. Jack Conan (Leinster/Old Belvedere) 36 caps
21. Jamison Gibson Park (Leinster) 23 caps
22. Ross Byrne (Leinster/UCD) 17 caps
23. Robbie Henshaw (Leinster/Buccaneers) 61 caps