Ciaran Brennan has agreed a deal which extends his contract with Wednesday until the summer of 2024.
The 21-year-old central defender has played eight first team games this season since returning from a loan spell with National League side Notts County.
Brennan told the club website: “I’m really happy, I’ve broken through this season and I want to progress my career with Wednesday.
“The gaffer has told me how well he thinks I have done, he wants me to stay, and I feel I am really developing playing under him and obviously I want that development to continue.”