Charlie Atkins beat Mikey Hardie to pole by 0.674secs with a hot lap of 1min 52.046secs.
Calum Beach, who set the pace in free practice, ended the day third quickest and a further half second behind. Kieran Kent will head the second row, with James McManus alongside in fifth.
HEL Performance British Junior Supersport Championship with Motocourse, Oulton Park, Qualifying:
1. Charlie Atkins (Symcirrus Motorsport) 1min 52.046s
2. Mikey Hardie (Completely Motorbikes/Affinity) +0.674s
3. Calum Beach (UPVC Outlet Racing) +1.225s
4. Kieran Kent (D&P Lovell Kent Racing) +1.310s
5. James McManus (Completely Motorbikes/Affinity) +1.560s