Cass Fjord is a fjord in northern Greenland. To the southwest, the fjord opens into the Kane Basin of the Nares Strait.

The Cass Fjord opens to the SW at the northern end of Peabody Bay, north of Cape Clay. Cass Fjord forms Washington Land's southeastern coastline and the facing shore is part of Daugaard-Jensen Land. The Washington Land shore is fringed by 180 m (590 ft) high cliffs, known as Poulsens Klint.

• List of fjords of Greenland
• Cass Fjord Formation

• Stratigraphy of the Cass Fjord Formation (Middle and Upper Cambrian), North Greenland