This study aims to investigate ultrasound (US) findings on salivary glands (SG) in patients with Sjögren syndrome (SS) vs. other connective tissue diseases (CTDs) and to assess the relationship of SGUS abnormalities with autoantibody profile in both groups. We enrolled 81 patients, 45 diagnosed with SS (39 with primary SS, 6 with secondary SS) and 36 diagnosed with other CTDs. All patients underwent a prospective evaluation of sicca symptoms, a Schirmer's test, and a B-mode US assessment of the parotid and submandibular glands, all blinded to the diagnosis. Each SG was semi-quantitatively scored 0-3; a grade ≥ 2 was considered pathological. SGUS involvement was classified as normal or pathological at the patient level and for each pair at the gland level. In addition, a total SGUS score of 0-12 and a parotid/submandibular score of 0-6 were calculated for each patient. Autoimmunity laboratory data were also obtained. All SGUS scores were higher in SS patients than in those with CTD (p < 0.001) and significantly more SS patients showed a pathological global (p < 0.001), parotid (p < 0.001), or submandibular (p = 0.001) US score compared with CTD patients. In SS patients, the presence of autoantibodies was significantly associated with pathological SGUS and higher scores, particularly at the parotid level, while in CTD patients, xerostomia and a pathological Schirmer's test were associated with pathological US and higher scores at the submandibular level (p < 0.05). SGUS showed a different grade of abnormality, site involvement, and associated autoantibody profile in SS patients as compared with other CTD. KEY POINTS: • Patients with SS and other CTDs showed different grades of SGUS abnormality. • Patients with SS and other CTDs showed different gland involvement and associated autoantibody profiles. • Anti-Ro60 and anti-Ro52 Ro60 positivity were associated with the severity of parotid involvement in SS patients.