The deals were announced by the Lilywhites an hour apart on Wednesday afternoon, the pair having come through PNE’s academy.
O’Neill, 17, has played three times as a substitute for North End’s first-team in the past month.
He’s been a regular scorer at youth-team and reserves level and will be part of the senior squad next season.
O’Neill, who turns 18 in early June, has signed a two-year contract to June 2024, with the club having an option of a further year.
The deal for Bennett is a one-year contract with the option of a further year held by North End.
O’Neill said: “I’m really happy to get the deal sorted and now I can focus on making my way into the first team, cementing my place around the squad and hopefully making more appearances.
“I can’t wait for July to come now so I can get back to playing, impressing the manager and hopefully I can start playing as soon as possible.”
Bennett has battled back from a serious knee injury to be in a position to sign a professional deal at the end of his two-year scholarship.
He tore his anterior cruciate ligament towards the end of last season and was out for 10 months before returning to action in February.
The attacking midfielder bagged 11 goals for the Under-19s in league and cup action after his return.
Bennett said: “My aim is just to kick off pre-season well, to start fast and see how I go for the beginning of the season.
“I’m ready to try and make an impact as soon as I can.”
With North End operating with a smaller squad next season after the numbers became bloated this campaign, O’Neill and Bennett have every chance of being in first-team contention.
A number of youngsters at PNE have pro deals. Lewis Leigh signed his at the start of the season.
Harry Nevin had a pro deal agreed when first signed his scholarship two years ago, while first-year scholars Noah Mawene and Josh Seary agreed pro contracts when they turned 17.
Dana Amaral, in the same age group as O’Neill, Bennett, Nevin and Leigh, has had his contract extended.