Iliotibial band syndrome or friction syndrome is an overuse disorder of the lateral knee. It is commonly reported in athletes, such as runners and cyclists, and refers to pain related to physical activity. The diagnosis is based on clinical history and physical assessment. Imaging, including ultrasound, is mainly performed in recurrent or refractory cases. The purpose of this paper is to review the etiology, diagnosis, and therapy of iliotibial band syndrome with a focus on ultrasound imaging and ultrasound-guided treatment. Ultrasound findings include soft-tissue edematous swelling or discrete fluid collection, suggestive of bursitis, between the iliotibial band and the lateral femoral epicondyle. The thickening of the iliotibial band has been inconsistently reported. Treatment varies according to the disease phase and, in the acute phase, consists of rest, physical therapy, and anti-inflammatory medications. Ultrasound-guided local steroid injections are effective in relieving symptoms.