In human medicine, central nervous system (CNS) concussion is defined as a transient neurological dysfunction following a traumatic event, without evidence of structural abnormalities of the affected region on advanced diagnostic imaging. Depending on the anatomical region involved, three forms of concussive syndromes are described: brain concussion, spinal concussion and cerebellar concussion. Although major textbooks of veterinary neurology admit the existence of canine brain concussion, spontaneous cases of this pathological condition have not been reported in small animals so far. This report describes two cases of concussion in dogs: a 9-month-old, intact male, shih-tzu with brain concussion; and a 10-month-old, intact male, poodle with cerebellar concussion. In addition, a brief review of the definition of the term "concussion" in the veterinary medical literature is provided, in comparison to its meaning in the human medical literature. Finally, this paper proposes an appropriate definition of "concussion" in dogs, that may facilitate clinicians in the recognition of such an elusive syndrome.