Moccasin is a Native American word, of which the spelling and pronunciation vary in different dialects, a shoe made of deerskin or other soft leather. It is made in one piece; the sole is soft and flexible and the upper part is often adorned with embroidery, beading or other ornament. It is the footwear of the North American Indian tribes and is also worn by hunters, traders and settlers.

In New Zealand and Australia sheep shearers make for themselves footware consisting of part of a cured sheepskin with the wool inside to use while working; these moccasins protect the feet, provide good grip on wooden floors and soak up the sweat of the wearer while not hurting the animal.

In botany, the lady's slipper is known in the United States of America, as the moccasin flower, from its resemblance to a shoe or moccasin.

The name moccasin is also given to a venomous snake found as far north as North Carolina and westward to the Rocky Mountains, and popularly called cottonmouth from the white rim around the mouth. It belongs to the family Crotalidae, species Ancistrodon (or Cenchris) piscivorus, is about two feet long and is often found in marshy land. It is sometimes called the water moccasin to distinguish it from the upland moccasin (Ancistrodon contortrix or atrofuscus), which is commonly called copperhead and is found further north in dry and mountainous regions. The name is possibly a distinct word of which the origin has not been traced.