Tendon-related disorders are a common condition in both sports medicine and orthopedic clinical practice. Ultrasonography, power doppler, and magnetic resonance imaging (MRI) are the most widespread technologies, but the use of ultrasound elastography—including strain elastography and shear wave elastography—has been increasing in the last years. The aim of this paper is to evaluate the use of ultrasound elastography in tendon-related disorders. Research in PubMed, Scopus, and Web of Science databases is performed, and 364 papers are exported. After the study selection process, 38 papers are included in this systematic review. The risk of bias of each paper is evaluated using the RoBANS tool. Blinding, confounding variables, and measurement of exposure are the most affected items. From the included papers, tendinopathy is the most analyzed pathology, followed by tenosynovitis and rotator cuff disease. The Achilles tendon, patellar tendon, and common extensor tendon of the hand are the most analyzed tendons. Ultrasound elastography results in being the method providing good sensitivity and specificity (up to 100% and 100%, respectively, in tendinosis of the long head of the biceps tendon, in transverse plan examination) and accuracy (up to 97.8% in Achilles tendinopathy); furthermore, this technique is able to ensure real-time feedback on tissue elasticity and appears more sensitive than B-mode alone.