<p>This study experimentally aimed to evaluate the torsional capacity of double web thin-walled steel tubular beams under pure torsion. The parameters that were studied in this research include depth to web or flange thickness ratio in hollow steel Section&#xa0;(3, 4, and 6 mm), filled and hollow steel tube, compressive strength value of the infill concrete (nonstructural, normal, and high strength), density of the infill concrete (normal and lightweight), and stiffener number (4, 5). The number of test specimens was fourteen. The depth of a double web steel section was 190 mm, with a width of 115 mm, length of 1200 mm, and the torsion arm was 450 mm. The test results showed that increasing web thickness has a noticeable effect on the torsion bearing capacity compared to an increase in flange thickness. Tubular steel filled with concrete gives an increase in the torsional capacity of about 70%. Also, the increase in compressive strength leads to an increase in torsional capacity and stiffness. The lightweight concrete recorded a slight decrease in torsional capacity and stiffness but an increase in ductility and rotation angle compared to the normal concrete. Also, the test results indicated that the effect of stiffener number has effect on torsional capacity were increasing one stiffener leads to an increase in rotation angle and ductility by about 13.7%, and 23.6% for hollow steel tube, but decreased by about 11.2% and 15% for concrete filled steel tube respectively. A comparison between the experimental results and the calculations from the AISC and Eurocode 4 codes revealed that the codes provided more conservative values for torsional capacity.</p>