'NCIS' star Mark Harmon placed equally third on the list, alongside Jim's co-stars Simon Helberg and Kunal Nayya, as well as 'Two and a Half Men' actor Ashton Kutcher, with all of them earning $20 million each.
'Two And A Half Men' star Jon Cryer placed seventh, equally with 'Everybody Loves Raymond's Ray Romano, despite the last series ending in 2005.
'The Mentalist's Simon Baker and 'Grey's Anatomy's Patrick Dempsey earned $12 million each, completing the top ten.
The news that 'The Big Bang Theory' stars dominate the list won't surprise fans as it was recently revealed the three main characters, played by Jim, Johnny and Kaley Cuoco, are reportedly being paid $1 million per episode for their part in the show.
A source said at the time: "[They will get] larger pieces of the show, signing bonuses, production deals and advances towards the back-end."
Bosses also reportedly spoke to Simon and Kunal to ensure their paycheques were brought more in line with that of the three main characters.
Forbes' Highest-Earning TV Actors of 2015:
1. Jim Parsons, $29 million
2. Johnny Galecki, $27 million
3. Mark Harmon, $20 million
4. Simon Helberg, $20 million
5. Kunal Nayya, $20 million
6. Ashton Kutcher, $20 million
7. Jon Cryer, $15 million
8. Ray Romano, $15 million
9. Simon Baker, $12 million
10. Patrick Dempsey, $12 million