The 29-year-old moved to Elland Road from FC Lugano in the summer of 2017 and went on to make 171 appearances for the Whites, scoring 22 goals during his four-year stay, as well as playing a key role as the club won promotion to the Premier League as Championship title-winners in 2020.
A statement on the club website confirmed: “Whilst the club made offers for Gjanni to stay, we have been unable to reach an agreement with his representatives and his existing contract expired last week.”
Leeds director of football Victor Orta praised the North Macedonia international following the end of his time at Elland Road.
“I knew Gjanni was going to be special the moment he walked into the building,” said Orta. “The emotion I saw in his face and the face of his parents when he signed his contract here at Elland Road was a beautiful moment and I was sure he was going to give everything for Leeds United.
“Even with this in mind he exceeded my expectations. Gjanni has been exceptional both on and off the field, his team mates will miss him greatly, as will all of the staff at Thorp Arch and Elland Road.
“We thank Gjanni for all of his efforts and we wish him every success for the future.”
Alioski played 36 of Leeds’ 38 games in the Premier League last season, scoring twice, as Marcelo Bielsa’s team finished ninth on their return to the top flight.