MALMÖ, May 31, 2014 (AFP) - The pair led the field on 13 under after Stenson shot a 64 for the best round of the day with Pepperell signing for a 65.
One shot behind came Stephen Gallacher and Alvaro Quiros.
Stenson, the world number two, shot seven birdies and an eagle at the seventh to join overnight leader Pepperell who is searching for his first European Tour win.
I had great fun out there," said the unheralded Briton.
"I felt comfortable out there.
"I'm really happy with myself. The game feels pretty good.
"It was a great start with three birdies in a row. I was flying and I missed good opportunities on four and five. Then I had a sticky spell with my swing, but hung in there. I would like to have finished with a birdie on the last two holes, but I'm not too unhappy about that.
"On 17 I had a good swing, bad putt. On 18 I just hit a slight pull and the wind just took it in the water, but I can't be too disappointed as I committed fully.
"Henrik is tied with me so it is going to be a great day tomorrow (sunday), but I've just keep to keep focused on my game and do what I've been doing. If I do that I'll have a shot come the last and I'll enjoy it."
Stenson, reflecting on his eagle magic at the seventh, said: "I knew it was going to be inside ten feet when I hit it and it landed about five feet away, had a little release and hop and went in."
Leading third round scores in the EPGA Nordea Masters in Malmo on Saturday (GBR & IRL unless stated, par 72):
203 - Eddie Pepperell 66 72 65, Henrik Stenson (SWE) 69 70 64
204 - Stephen Gallacher 67 72 65, Alvaro Quiros (ESP) 71 67 66
205 - Victor Dubuisson (FRA) 69 69 67
206 - Bradley Dredge 69 70 67
207 - Romain Wattel (FRA) 71 70 66, Rafael Cabrera Bello (ESP) 68 72 67, Thongchai Jaidee (THA) 69 70 68
208 - Robert Jan Derksen (NED) 70 71 67, Christopher Doak 70 69 69
209 - Thomas Bjorn (DEN) 70 71 68, James Morrison 70 73 66
210 - David Howell 73 70 67, Jens Dantorp (SWE) 66 73 71, Tom Lewis 71 71 68, Rikard Karlberg (SWE) 67 75 68, Thomas Pieters (BEL) 73 69 68, Pablo Larrazabal (ESP) 70 72 68
Selected
211 - Raphael Jacquelin (FRA) 72 70 69
213 - Peter Hanson (SWE) 69 71 73, Edoardo Molinari (ITA) 71 69 73
214 - James Kingston (RSA) 72 70 72, Kevin Phelan (USA) 71 70 73
215 - Jeev Milkha Singh (IND) 71 74 70, Wade Ormsby (AUS) 69 74 72, Gregory Havret (FRA) 71 74 70
217 - Miguel Angel Jimenez (ESP) 69 73 75, Richard Green (AUS) 72 69 76, Peter Lawrie 75 70 72
218 - Daniel Im (USA) 72 72 74