The centre-back will further boost the Gunners' title charge after he starred at the World Cup, playing almost every minute of his country's campaign.
Advertisement
The 22-year-old will offer plenty of depth for Mikel Arteta, who currently has four centre-back options in the shape of Gabriel Magalhaes, William Saliba, Rob Holding and Ben White, although he has excelled after moving to right-back this season.
But with the games coming thick and fast, and Arsenal's Europa League campaign to resume, Kiwior will ease the workload at the back as they aim to maintain their Premier League lead.
The defender, who has also turned out in central midfield in Serie A, joined Spezia from Slovak side Zilina in 2021, and has gone on to impress in Italy.
Advertisement
If the deal is completed, Kiwior will join Leandro Trossard in moving to the Emirates in the winter window, with the Belgium midfielder in London for a medical.
Joining from Brighton in a £27m move, Trossard is another huge boost for Arsenal's trophy pursuit.
The 28-year-old has been one of the stand-out players in England this season, with seven goals and two assists in the league, which included a hat-trick against Liverpool at Anfield.
Advertisement
Advertisement
Arsenal currently sit five points clear at the top of the Premier League after a convincing 2-0 win over Tottenham in the north London derby.