Office Tab Enterprise

Office Tab Enterprise screenshots

Open, view, and edit multiple MS Office documents in a single tab
Office Tab Enterprise 10.5 : Settings Window

Alternative downloads

Office Tab Center
The tabbed interface allows you to open multiple documents in a single window.
WPS Office Premium
Create and edit all sorts of documents, spreadsheets, and presentations.
Spire.Office for .NET
Suite of Office .NET Components to open, modify, convert, and view Office files.