Purpose: To investigate the diagnostic performance of gray-scale ultrasound (US) and shear wave elastography (SWE) for determining salivary gland involvement primary Sjögren's syndrome (pSS). Methods: In this prospective study, the salivary glands of 72 healthy volunteers and 74 participants with pSS were examined by two blinded radiologists with consensus using gray-scale US and SWE. SWE parameters were compared between groups. The area under the curve (AUC), sensitivity, and specificity of gray-scale US and SWE was analyzed. The correlation between SWE and clinical findings was investigated. Result: The SWE parameters of the parotid and submandibular glands were significantly higher in the pSS group, but did not differ significantly based on serologic assays, Schirmer test, minor salivary gland biopsy, and comorbidities. The AUC values for gray-scale US of the salivary glands were significantly lower than the AUC values for SWE. The elasticity modulus (kPa) of parotid gland had the highest AUC value (0.937; 95% CI, 0.901–0.973), with a sensitivity of 93.2% and a specificity of 83.3%. SWE had no correlation with age, disease duration, laboratory values, or disease activity. Conclusion: SWE provides excellent diagnostic performance for submandibular and parotid gland involvement in pSS and can be used to complement gray-scale US.