The invention relates to an exhaust-gas turbocharger (1) having a compressor housing (3), having a bearing housing (28) which can be connected at one end to the compressor housing (3) by means of a first fastening device (19), and having a turbine housing (2) which can be connected to the bearing housing (28) at the other end of the latter by means of a second fastening device (20), with the compressor housing (3), the bearing housing (28) and the turbine housing (2) extending along an exhaust-gas turbocharger longitudinal axis (R), wherein the first fastening device (19) is designed as a plug-and-twist connecting device.