The regulator said the proposed acquisition "would raise no competition concerns" within the European Union.
In analysing the bid, it found that "Microsoft and Nuance offer different products" and the company will continue to face "strong" competition from other firms in the future.
The US and Australia had both signed off on the purchase, but it's not yet a done deal. On 13 December the UK's Competition and Markets Authority said it would investigate the transaction. With the regulator accepting public comments until 10 January, 2022, it's unlikely the deal will close by the end of 2021 as Microsoft had said it would when it first announced its intention to buy Nuance.
In April, Microsoft agreed to acquire the speech-to-text software company, claiming the acquisition was about increasing its presence in the healthcare vertical.