Ramsey will join Juventus after his Arsenal contract expires this summer. It's understood that he'd been discussing a move for a number of weeks before coming to an agreement Wednesday, which will make him the second-highest earner at the club behind Cristiano Ronaldo.
Juventus had initially hoped that Ramsey would join them this month, but Arsenal were unwilling to sign off on an early exit.
The agreement will bring an end to Ramsey's 10-year career in north London, where uncertainty over his future has persisted throughout the season.
The two sides were engaged in contract talks last summer before Arsenal allegedly withdrew their offer to Ramsey. The 28-year-old later revealed his surprise at the Premier League club's decision to take their offer off the table and demanded an explanation, as he thought they'd reached an agreement.
Juventus had emerged as the leading contender to sign the 28-year-old. Bianconeri manager Massimiliano Allegri is believed to be a massive fan of Ramsey.
The midfielder has played in over 250 top-flight matches and scored 52 goals for the Gunners following his £4.8-million transfer from Cardiff City in 2008. He also scored the winning goals to help Arsenal capture the FA Cup in 2014 and 2017.
Ramsey is expected to be inserted into a three-man midfield scheme at Juventus, featuring Miralem Pjanic and Blaise Matuidi. His arrival is expected to result in reduced opportunities for the likes of Emre Can, Rodrigo Bentancur, and Sami Khedira.