Bayern Munich, Paris Saint-Germain and Real Madrid were also linked with the player, but Juve have won the race to secure his signature.
Ramsey will earn around £400,000 per week at Juventus, making him the highest-paid British player of all time.
The Welshman has agreed to a four-year contract and his salary will raise to 21 million euros per season.
Ramsey was free to open talks with any club from 1 January 2019 as he was in the final six months of his contract. The deal carries with it no transfer fee as his Arsenal contract expires on June 30.
Ramsey leaves Arsenal after nearly 11 years at the club, and it's believed he will earn £400,000 per week in Turin, making him the highest paid British player in the world.
Ramsey, 28, issued his own statement via Instagram.
He wrote: "You welcomed me as a teenager and have been there through all the highs and lows I've encountered during my time at the club".
Ramsey signed for Arsenal from Cardiff City in the summer of 2008 and despite having faced hardships in the initial parts of his career with the Gunners owing to injuries, the Wales global had grown into an integral part of the team in recent years.
In his 11 years at Arsenal, Ramsey has made over 350 appearances in all competitions, scoring 61 goals. It is with a heavy heart I leave after 11 incredible years in north London.
"I will continue to give the team 100% and hope to finish the season strongly, before heading onto my next chapter in Turin". He has always been a consummate professional and will always have a special place in the hearts and memories of Arsenal fans around the world'.
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