The Royal Borough of Windsor and Maidenhead wants to support an existing grammar school to develop a satellite school in the borough.
The authority said it was currently working on the plans with Marlow's Sir William Borlase's Grammar School.
If it goes ahead, the two-form entry school, would open by 2021 at the latest.
The authority, which has already spent £80,000 on a feasibility study, will now decide whether to approve spending up to £200,000 on a consultation and site search at a cabinet meeting on 29 October.
It comes as the government recently gave the go-ahead to a new grammar school in Kent which will be built as an "annexe" of an existing school 10 miles away.
A Berkshire council is examining the possibility of building a £20m grammar school in Maidenhead.