Our aim was to review the clinical applications of diffusion-weighted magnetic resonance imaging in the head and neck. Diffusion-weighted magnetic resonance imaging plays a role in the differentiation of benign from malignant head and neck tumors, squamous cell carcinoma from lymphoma, and metastatic from benign lymphadenopathy as well as in the selection of the biopsy site. It can be used for the differentiation of recurrent tumors from posttreatment changes and in monitoring the patient after radiotherapy. It helps in the differentiation of necrotic tumors from abscesses. Additionally, it can be used for the diagnosis and grading of diffuse autoimmune diseases, such as Sjogren and Graves diseases.