BACKGROUND: To investigate the role of shear wave elastography (SWE) in patients with lateral epicondylitis (LE) by assessing the common extensor tendon (CET) elasticity. METHODS: A total of 62 unilateral LE patients were enrolled. Shear wave speed (SWS) and the thickness of CET in both elbows, along with the involved elbows with pre- and post-treatment, were obtained by SWE. The differences between groups, inter- and intra-observer agreements, and diagnostic accuracy were analyzed with a paired -test, intraclass correlation coefficients (ICCs), and receiver operator characteristic (ROC) curve, respectively. RESULTS: LE patients had significantly lower SWS on lesion sides compared to healthy elbows (P<0.05). The SWS of involved elbows were significantly higher after non-operation treatment than before treatment. The inter- and intra-observer agreements were excellent (ICCs: 0.900-0.993) for SWE measurements. Moreover, a 12.2 m/s cutoff value of mean SWS ( ) for discriminating LE patients from healthy subjects revealed a sensitivity and specificity of 93% and 93%, respectively. CONCLUSIONS: SWE is a valid imaging technique for the diagnosis of LE and monitoring of the treatment effect. Future studies are essential for investigating the correlations among clinical examinations, conventional ultrasound, and SWE.