The Shetland's roots go back over a thousand years, probably to sheep brought to the Shetland Islands by viking settlers. They belong to the Northern European short-tailed group which also contains the Finnsheep, Norwegian Spaelsau Icelandics, Romanovs and others. The Shetland is the smallest of the British breeds and it retains many of the characteristics of wild sheep. Today they are considered a primitive or "unimproved" breed. Rams usually weigh 90 to 125 pounds and ewes about 75 to 100 pounds. Rams usually have spiral horns, whereas the ewes are typically polled. They are fine-boned and their naturally short, fluke-shaped tails do not require docking.

     Shetland wool has a Bradford count usually in the upper 50's to lower 60's and a fiber diameter range of 20-25 microns. Fleeces usually weigh between 2 and 4 pounds (1-1.5 kg) and have a staple length of 2 to 4.5 inches (50-120 mm). Shetland comes in one of the widest ranges of colors of any breed. Besides the white, the sheep produce several shades of wool including moorit (reddy/brown), shaela (silvery grey), fawn, grey, dark brown and black. They are often patterned such as krunet (white crown), katmoget (dark belly) and gulmoget (light underneath). There are eleven main colors as well as thirty markings, many still bearing their Shetland dialect names. Unfortunately, many of these colors and markings have become quite rare as white wool has historically commanded better prices. The wool color and high quality is commercially important to the wool industry of the islands where natural wools are often used undyed to make high quality shetland knitwear. Extra fine ring shawls are knitted, so called because the finest can be passed through a wedding ring. In the UK as a whole the wool is prized by handspinners.

     Shetland sheep are very hardy, good mothers, easy lambers and produce plenty of milk. When crossed with an early maturing terminal sire (such as a Ryeland) the fat lambs make excellent eating and dress out well. Purebred Shetland meat is highly regarded on taste, but is slow to mature and wethers are often run through to shearlings. In the U.S. the North American Shetland Sheepbreeders Association (NASSA) was established in coordination with the Shetland Sheep Breeders' Group of the Rare Breeds Survival Trust in the UK. The purpose of the association is to assist breeders of Shetland Sheep in North America in maintaining the purity and quality of the breed and to provide accurate registration and pedigree records for informed breeding decisions.