The fifth series of QI; all of its episodes involve a topic beginning with E. This series began on 21 September 2007 and ended on 14 December 2007; it featured the "Elephant in the Room" bonus.
| # | Title | Guests | Winner(s) | Original Air Date | Notes |
| 1 | Engineering | Bill Bailey Rob Brydon Jimmy Carr |
Rob Brydon | 21 Sep. 2007 | |
| 2 | Electricity | Jo Brand Rich Hall Sean Lock |
Jo Brand | 21 Sep. 2007 | |
| 3 | Eating | Jimmy Carr Phill Jupitus Johnny Vegas |
Alan Davies | 28 Sep. 2007 | This episode marks Johnny Vegas' first appearance on the show. |
| 4 | Exploration | Bill Bailey Rich Hall Sean Lock |
Rich Hall | 5 Oct. 2007 | |
| 5 | Europe | Phill Jupitus David Mitchell Dara Ó Briain |
Phill Jupitus | 12 Oct. 2007 | |
| 6 | Everything, Etc. | Clive Anderson Jeremy Clarkson Vic Reeves |
Vic Reeves | 19 Oct. 2007 | |
| 7 | Espionage | Clive Anderson Jo Brand Vic Reeves |
(Tied) Clive Anderson and Vic Reeves | 26 Oct. 2007 | |
| 8 | Eyes & Ears | Jimmy Carr Phill Jupitus David Mitchell |
Alan Davies | 2 Nov. 2007 | |
| 9 | Entertainment | Bill Bailey Jo Brand Jeremy Clarkson |
Jeremy Clarkson | 9 Nov. 2007 | Children in Need special. |
| 10 | England | Charlie Higson Phill Jupitus Sean Lock |
The Audience | 16 Nov. 2007 | |
| 11 | Endings | Jimmy Carr Doon Mackichan Dara Ó Briain Pudsey Bear |
(Tied) Jimmy Carr and Dara Ó Briain | 23 Nov. 2007 | |
| 12 | Empire | Bill Bailey Jo Brand Sean Lock |
Alan Davies | 7 Dec. 2007 | Christmas special |
| 13 | Elephants | All E Series guests except for Doon Mackichan and Pudsey Bear. | N/A | 14 Dec. 2007 | This is a compilation video and not a true episode. |