Ophthalmic ultrasound imaging is based on the emission of an acoustic pulse and reception of the pulse after it has been reflected off ocular tissues. It has been used in the form of A- and B-scans for many decades. Ultrasound biomicroscopy (UBM) is a new imaging technique that uses high-frequency ultrasound to produce images of the eye at near microscopic resolution. This chapter will review the various applications of the UBM for glaucoma and illustrate how it can be a useful tool in the management of various conditions. The technology for UBM, originally developed by Pavlin, Sherar, and Foster, is based on 50- to 100-MHz transducers incorporated into a B-mode clinical scanner. This chapter covers the image acquisition and clinical applications. Images are acquired with the patient lying supine. Room illumination, fixation, and accommodative effort affect anterior segment anatomy and should be held constant, particularly when quantitative information is being gathered.