Introduction:Triple-negative breast cancer (TNBC) is well known for its unique clinical and pathological characteristics. Our study compared the sonographic features of TNBC with those of non-TNBC according to the sonographic classification system of the American College of Radiology's Breast Imaging Reporting and Data System (BI-RADS). Methods: This was a retrospective study involving sonographic images from 50 patients with TNBC and 52 patients with non-TNBC diagnosed from 2016 to 2020, which were reviewed by two reviewers simultaneously according to the fifth edition of BI-RADS and a result was reached by consensus. Results: TNBCs were significantly associated with higher tumour grade (p < 0.001), higher tumour stage (p = 0.006) and larger tumour size (p < 0.001). Compared with non-TNBCs, TNBCs had a significantly higher incidence of the following features: oval or round shape (p = 0.006), microlobulated margin (p = 0.006), parallel orientation (p = 0.001), posterior acoustic enhancement (p = 0.007), and less architectural distortion (p < 0.001). Conclusions: TNBCs have their own distinct sonographic features compared with non-TNBCs. Clinicians should be alert to these features since they mimic a benign lesion but show aggressive clinical behaviours.