Cheltenham Library will close from 14 May to allow essential building works.
The site is expected to reopen on 1 June, although this could be extended if needed.
Gloucestershire County Council says asbestos was identified during earlier maintenance and needs to be safely removed.
While the main building is shut, the Children’s Library will remain open and some services will continue.
Residents are also being encouraged to use nearby libraries including Charlton Kings Library, Hesters Way Library and Prestbury Library.