Antman failed to establish himself as a regular in a turbulent season at Ibrox, where Rangers made a poor start under Russell Martin before losing out to Celtic and Hearts to finish third in the three-way title race.
In total, the 24-year-old played 28 times for Rangers in all competitions, and made 16 appearances in the league, scoring once. He arrived on a four-year contract from Dutch side Go Ahead Eagles, and has signed a deal of the same length at Anderlecht.
The Glasgow side have still managed to turn a profit despite Antman being surplus to requirements - they bought him from Go Ahead Eagles for €3 million a year ago. Belgium will be the fourth country outside Finland that the winger will have played in, having left Gnistan for Denmark's Nordsjaelland in 2019.
Antman still managed to maintain his place in the Finland side while a Glasgow resident, winning 12 caps in the last year, taking his tally to 31.
Tonight (30th July), Anderlecht take on Swedish side Hammarby in the second leg of their UEFA Europa League second qualifying round tie, with the scores poised at 1-1 after the first leg in Stockholm.