Short Descriptions from the Full Standard

appearance The Leonberger is a large, elegant, balanced dog with a double coat and a medium temperament. The Leonberger displays a proud head carriage and always has a black mask and a kind and intelligent expression. The Leonberger, true to its origins as a working dog, is surprisingly agile for its size and strength, and is elegant in movement. Males should always appear masculine and females feminine; the gender should be easily recognizable.
size The height measured at the withers is 28 to 31.5 inches for males, with 30 inches preferred, and 25.5 to 29.5 inches for females, with 27.5 inches preferred. The Leonberger has a slightly rectangular build, with proportion of height to length about nine to ten, and front and rear angulation is equal, creating a balanced, harmonic outline.
head One of the hallmarks of the breed is its head and expression. The correctly proportioned head is deeper than broad and the length of muzzle and the length of skull is approximately equal. The head always has a black mask which should extend to above the eyes. The expression of the Leonberger is good-natured, kind, and intelligent. The nose and lips are always black. Eyes are oval to almond shaped, medium-sized, and dark brown, with eyelids closing tightly. Ears are fleshy, pendant, and moderate in size, hanging close to the head with the tips level with the inside corners of the mouth. Ears are set slightly forward and are level with the top of the skull. The lower jaw is strong, with lips fitting closely with no drooling. Bite is scissor with full dentition, although level bite is accepted.
topline The Leonberger is well muscled with a proudly carried neck which flows smoothly into withers. Shoulders are well-laid back, and topline is level to the rump. Prosternum is pronounced and ribs are well-sprung and oval-shaped, supporting a moderately broad and roomy chest. Depth of chest reaches the elbows and underline is only slightly tucked up. The back and loin are broad and strong with a slightly sloping croup. The tail is set just below the level of the back and should reach the hock and is well furnished. When relaxed, the tail hangs straight down or slightly curved up at the end.
coat The double coat of the Leonberger is water-resistant and is characterized by shorter, finer hair on muzzle and limbs. The outer coat is long, profuse, relatively straight, and ideally lies flat, allowing for the silhouette to be seen. The mature male Leonberger has a pronounced mane, giving a lion-like appearance. There is ample feathering on the back of forelegs and hind legs. Depending on the climate and season, undercoat should be present and is soft and dense. Apart from a neatening of the feet, the Leonberger is presented untrimmed. A variety of coat colors is acceptable, including all combinations of lion-yellow, red, red-brown, and sand. The outer coat may have black tips which should never dominate the overall color.
gait The Leonberger has an efficient, balanced, ground-covering gait, and is graceful and free in movement. The topline must remain level in movement. At a trot, viewed from the front or rear, the legs travel straight. As speed increases, the front and rear legs have a tendency to converge toward the centerline.
temperament First and foremost a family dog, the Leonberger’s temperament is one of its most important characteristics. When well trained and socialized, the Leonberger is self-assured, insensitive to noise, and friendly toward children and adults alike, able to be taken anywhere without difficulty and adjusting well to a variety of circumstances.

View the AKC Standard for the Leonberger in detail.