OBJECTIVE: To investigate sex-based sonographic differences in patients with psoriatic arthritis (PsA). METHODS: The study population included consecutive prospectively recruited patients with PsA, as determined by the CASPAR (Classification for Psoriatic Arthritis) criteria, who underwent clinical and physical examinations, followed by a detailed ultrasound (US) evaluation (greyscale and Doppler). US evaluation included 52 joints, 40 tendons, and 14 points of entheses (Modified Madrid Sonographic Enthesis Index [MASEI] plus lateral epicondyles) performed by an experienced sonographer blinded to the clinical data. The US score was based on the summation of a semiquantitative score for synovitis, tenosynovitis, and enthesitis. The US enthesitis score was categorized into inflammatory lesions (ie, hypoechogenicity, thickening, bursitis, and Doppler) and structural lesions (ie, enthesophytes/calcifications and erosions). RESULTS: The study population of 158 patients included 70 males and 88 females. The males had higher rates of employment ( = 0.01), Psoriasis Area and Severity Index scores ( = 0.04), and mean swollen joint counts ( = 0.04). The total US score and its subcategory scores-the synovitis and tenosynovitis scores-were similar for both sexes, whereas the total enthesitis score and its subcategory score-the inflammatory enthesitis score-were significantly higher for the males compared to the females ( = 0.01 and = 0.005, respectively). Hypoechogenicity, thickening, and enthesophytes were more prevalent in males compared to females ( < 0.05). Multivariate ordinal logistic regression models showed that male sex was associated with a higher US inflammatory enthesitis score compared to female sex (odds ratio 1.96, = 0.02). CONCLUSION: Sonographic enthesitis was more prevalent in males compared to females with PsA. These differences were not reflected by enthesitis disease activity scores derived from clinical assessment.