An exhaust-gas turbocharger (1), having a shaft (2) which has an outer diameter (A2); a turbine wheel (5) which is fastened to the shaft (2); and a connecting device (8) via which the shaft (2) is fastened to the turbine wheel (5). The shaft (2) has, in the region of an end side (3), a shaft shoulder (4) with an outer diameter (A4) larger than the outer diameter (A2) of the shaft (2). The turbine wheel (5) has an external thread portion (7) integrally formed on its wheel rear side (6) The connecting device (8) has a sleeve nut (8A) which is screwed onto the external thread portion (7) and, in a process, engages behind the shaft shoulder (4) in order to brace the shaft (2) against the turbine wheel (5).