The Griffon Bruxellois is a small dog with a sturdy build, weighing 7–12 pounds and standing 18–20 centimetres at the withers. It has a square proportion, with its length matching its height. It has a domed-shaped head, short nose with large nostrils, and huge, shiny eyes that are set wide apart and naturally adorned with long, black lashes. Its eyes are also its distinct and memorable feature that gives it an almost-human expression. The Griffon Bruxellois has small ears set high above the head and can either be cropped or not. It has medium-length, well-muscled forelegs, an arched neck, and a levelled back that add to its robust appearance.
The Griffon Bruxellois wears either a rough and wiry dense coat or a straight, smooth, and glossy coat. It often comes in a variety of colours, including red, reddish brown, beige, black and tan, and solid black. Grooming-wise, whether it's low- or high-maintenance will largely depend on the type of coat. The rough-coated Griffon Bruxellois will require several brushing per week, including hand-stripping every three months, whilst the smooth-coated Griffon will only require at least once a week of brushing. Both coat types do not shed much, but the breed can't be considered hypoallergenic. Bathing for both should be done as needed.
Since the Griffon Bruxellois is a small dog breed, it is prone to gum diseases and as such should have its teeth brushed and cleaned on a regular basis. Also trim its nails once or twice a month to keep its nails in excellent condition and avoid overgrowth, cracking, and splitting. Ears should also be cleaned regularly to prevent ear infections. During grooming, make sure that you inspect all physical aspects of your Griffon Bruxellois, including lesions, fleas, ticks, and signs of infection such as redness, bad odour, and pain.