There are many alternatives to Okular for Linux if you are looking for a replacement. The best Linux alternative is Evince, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Okular and many of them are available for Linux so hopefully you can find a suitable replacement. Other interesting Linux alternatives to Okular are LibreOffice - Draw, KOReader, MuPDF and Koodo Reader.
Okular alternatives are mainly PDF Readers, but if you're looking for
Ebook Readers or PDF Editors you can filter on that. Other popular filters include
Linux,
Android,
Mac,
Open Source and
Windows. These are just examples - use the filter bar below to find more specific alternatives to Okular.
Gnome's project supplies no link of a Windows version.