The English side confirmed the deal via an official statement.
“Southampton Football Club is delighted to confirm the signing of Joe Aribo on a four-year contract from Rangers FC,” the club statement read.
The former Rangers FC midfielder was bought for a base fee of £6 million, which could rise to £10 million total fee based on add-ons.
The player’s medical tests were concluded yesterday and it was only a matter of time before the transfer became official.
The Super Eagles midfielder is deemed a top acquisition by the English side, haven caught the attention of many in last year’s Europa League Final loss to Frankfurt.