Clouded leopards are sexually dimorphic (with two distinct gender forms): the males are larger than the females. Clouded leopards are yellow-reddish-brown to yellow gray in color. Their fur has broad, dark brown or black bands that form nearly square or nearly circular shapes. They are named for these cloud-like patterns, which provide excellent camouflage. They also have broad black bands on their face. Clouded leopards' ears are black with a buff spot on the outside and white on the inside. Approximately six bands run across the nape of their neck. Their fur is short and coarse, their tail is very long, and their legs are relatively short. In relation to their body size, their upper canine teeth are longer than those of any other cat species and the largest upper canine relative to skull size of any carnivore. Also, they have a huge jaw gape (about 100 degrees) compared to 65 degrees for lions. In 2006, DNA studies identified the Sunda clouded leopard, Neofelis diard, which is native to Sumatra and Borneo, as a separate species from N. nebulosa.

Clouded leopards are rarely observed in the wild because they are arboreal with excellent camouflage, and under the best of circumstances they are hard to detect. They are endangered due mainly to habitat destruction, especially loss of primary tropical rain forest, but also because their fur brings a high price on the fur market. They are also vulnerable to the medicinal market and the pet trade in live animals. It is suspected that there are fewer than 10,000 mature individuals remaining in the wild. Radio collaring and camera trapping have greatly assisted study of clouded leopards in the wild.

• They are listed in Appendix I of CITES and protected by national legislation over most of their range.
• Listed as "vulnerable" on the IUCN Red List (International Union for Conservation of Nature and Natural Resources)
• CZS Conservation - Species Survival Plan
• Clouded Leopard Project
• Clouded Leopard Project Blog