Dortmund Sporting Director, Michael Zorc, thanked the Gabon international for his five years of service to the Bundesliga club.
"He has done great things for Borussia Dortmund," said Zorc. "Scored many important goals and is part of the team that brought the DFB Cup to Dortmund in 2017.
"We wish Pierre-Emerick all the best for his future at Arsenal. "
Football clubs around the world spent a record $6.37 billion on transfers in 2017 -- and this doesn't show any signs of slowing in 2018.
That $6.37 billion figure is a 32.7% increase in spending from the previous year, while a new record was also set with 15,624 international transfers.
Despite the exorbitant amount of spending, according to the annual report released by FIFA, just 15.8% of all transfers involved fees and more than two-thirds of all money spent came from only 50 clubs.
But elite teams, particularly in England, are not looking to tighten their purse strings in the first transfer window of 2018, with big-money deals having already been paid for Aubameyang, Philippe Coutinho, Alexis Sanchez and Aymeric Laporte.
Aubameyang's transfer from Borussia Dortmund to Arsenal was the first big deal to be completed on January's Deadline Day, often the year's most hectic 24 hours of the year for finalizing transfers.
The 28-year-old's move to Arsenal reportedly hinged on Dortmund's ability to find a suitable replacement, namely Chelsea's Michy Batshuayi, which then meant Antonio Conte's side had to fill the hole left by the Belgian.
The transfer merry-go-round involving Arsenal, Dortmund and Chelsea will be complete if the Premier League champions finalize the signing of Arsenal's Olivier Giroud.