The 27-year-old joined the Gunners from Atletico Madrid on transfer deadline day after the English club activated his £45 million release clause.
The amount involved in the transfer sees Partey overtake Michael Essien as the most expensive Ghanaian footballer of all-time.
Essien joined Chelsea from Ligue 1 side Lyon in 2005 in a deal worth £24.4 million, becoming the Blues’ record signing at the time.
No Ghanaian footballer has since commanded such a transfer in the last decade and half, until Arsenal paid £45 million to sign Partey from Atletico Madrid on Monday.
Partey will wear the number 18 shirt at Arsenal, and will reportedly be on a £250,000 per week wage.
The Ghanaian had been the target of transfer speculation all through the summer, having been linked with several elite clubs.
However, it was Arsenal who won the race for his signature after activating the midfielder’s release clause.
Here are the top five most expensive Ghanaian transfers of all-time:
1. Thomas Partey £50m (Atletico Madrid => Arsenal)
2. Michael Essien £24.4m (Lyon => Chelsea)
3. Baba Rahman £21.7m (Augsburg => Chelsea)
4. Andre Ayew £20.5m (Swansea => West Ham)
5. Asamoah Gyan £13m (Rennes => Sunderland)