Von Willebrand disease (VWD) is the most common hereditary blood-clotting disorder in humans. An acquired form can sometimes result from other medical conditions. It arises from a deficiency in the quality or quantity of von Willebrand factor (VWF), a multimeric protein that is required for platelet adhesion. It is known to affect several breeds of dogs as well as humans. The three forms of VWD are hereditary, acquired, and pseudo or platelet type. The three types of hereditary VWD are VWD type 1, VWD type 2, and VWD type 3. Type 2 contains various subtypes. Platelet type VWD is also an inherited condition.

In 2008 a new diagnostic category of "Low VWF" was proposed to include those individuals whose von Willebrand factor levels were below the normal reference range but not low enough to be von Willebrand disease (levels in the 30-50 IU/dL range). Patients with low VWF can experience bleeding, despite mild reductions in VWF levels.

VWD type 1 is the most common type of the disorder, with mild bleeding symptoms such as nosebleeds, though occasionally more severe symptoms can occur. Blood type can affect the presentation and severity of symptoms of VWD.

VWD type 2 is the second most common type of the disorder and has mild to moderate symptoms.

The factor is named after the Finnish physician Erik Adolf von Willebrand who first described the condition in 1926. Guidelines for the diagnosis and management of VWD were updated in 2021.