The quintet are all seen as crucial cogs in the future at GMHBA Stadium with much of its ageing list coming into the final years of their careers.
Holmes, O'Connor (2024) and Conway (2025) have signed two-year extensions, while Dempsey and Neale (2023) will stay put for next season with one-year deals.
Irish defender O'Connor is in his sixth season at Geelong since arriving from County Kerry as a teenager in 2016 and has tallied up 79 senior games since making his debut in Round 8 of his first season.
The 25-year-old plays predominantly in defence but has shown his ability in the middle to shut down the opposition's most important players.
Holmes was selected with the 20th pick in the 2020 National Draft and the speedster has since become a mainstay in Chris Scott's team in just his second season.
The 19-year-old suffered an ankle injury earlier this year but has played career-best football since his return with some encouraging displays against quality opposition.
Young guns sign on 🔫🤠 We've secured the signatures of five of the biggest and quickest Cats west of the bridge.
— Geelong Cats (@GeelongCats) July 19, 2022
Forward duo Dempsey and Neale both made their debuts this season in Rounds 6 and 11 respectively after both impressing at VFL level.
Plucked straight from school football in last year's Rookie Draft, Dempsey has put his raw talent on display in the reserves with his speed, leap and goalkicking ability making him a fan favourite already at the Cattery.
In his second season, Neale has been in strong goalkicking form in the VFL as he floats between the forward line and ruck duties. The Western Australian is quick and agile for his 203cm size and his ability to fly for marks has Cats fans excited for his future.
Untried ruckman Conway battled injury early in the season before playing a string of VFL games, where he has impressed with his ruck craft and physicality.
Cats General Manager of Football Simon Lloyd told geelongcats.com.au that the club was thrilled to secure the quintet's signatures and is excited about the future.
"It's a fantastic sign that Max, Mark, Ollie, Shannon and Toby see their futures here at the Cats," he said.
"Max and Mark both have outstanding character and take ownership over driving our Club standards. They play influential roles within our senior team and are consistently striving to improve the Geelong Football Club.
"For Ollie, Shannon and Toby, while limited in their AFL experience so far, they have all shown strong signs at VFL level and we are excited to see them take the next step in their development."