Officers from Surrey Police were called to Stanwell Hotel in Staines at 6.30 pm on Saturday to a report of a stabbing, the force said in a Facebook post.
The victim has been transported to hospital with “serious injuries”, it added.
A man in his 20s, who is a Somalian national, has been arrested on suspicion of attempted murder.
The force said: “Please can we ask that you do not speculate on this incident and we will continue to provide updates on this channel.”
The government first began using the hotel on Town Lane to house individuals and families seeking asylum in 2022.
Plans to return the site to wider community use were revealed earlier this year, alongside a proposed £10 million refurbishment.
The scheme would increase the hotel from 56 to 96 rooms and modernise it for business and leisure guests, including Heathrow Airport passengers.
Under the proposals, asylum seekers staying at the hotel would be expected to move out if planning permission is approved by Spelthorne Borough Council.

Technology & Business Editor