Tool holder (10; 110; 210) which is configured to rotate about a tool holder rotation axis that defines an axial direction, and which on its one axial longitudinal end (10a; 110a; 210a) has a tool portion (14; 114; 214) having a tool receptacle formation (18; 118; 218) for receiving a tool, and on its other axial longitudinal end (10b; 110b; 210b) has a coupling portion (16; 116; 216) having a coupling formation (20; 120; 220) for torque-transmitting coupling to a machine spindle of a machine tool, wherein provided on the tool holder (10; 110; 210) is a measuring device (28; 128; 228) for detecting data pertaining to the operation of the tool holder (10; 110; 210), which measuring device (28; 128; 228) comprises at least the following components: - at least one sensor (30, 32, 34, 36; 130, 136; 230, 236) which supplies a detection signal; - a signal transmission device (38; 138; 238) for transmitting a measurement signal from the measuring device (28; 128, 228) to a receiver device which is configured separately from the tool holder (10; 110; 210) and disposed remotely from the latter; - an electric circuit (40; 40a, 40b, 40c) for actuating the sensor (30, 32, 34, 36; 130, 136; 230, 236) and/or for processing the detection signal of the sensor (30, 32, 34, 36; 130, 136; 230, 236) and/or for actuating the signal transmission device (38; 138; 238), which for transmitting signals is connected to the sensor (30, 32, 34, 36; 130, 136; 230, 236) and the signal transmission device (38; 138; 238); and - a power supply device (42; 142) which for transmitting power is connected to the signal transmission device (38; 138; 238) and the electric circuit (40; 40a, 40b, 40c); wherein the tool holder (10; 110; 210) has a tool holder main body (12; 112; 212) which comprises the tool portion (14; 114; 214) and/or the coupling portion (16; 116; 216), wherein at least one component of sensor (30, 32, 34, 36; 130, 136; 230, 236), electric circuit (40; 40a, 40b, 40c) and power supply device (42; 142) is received in a recess (56, 62; 56a, 56b; 156, 162; 256) in the interior of the tool holder main body (12; 112; 212), characterized in that at least one sensor as tool portion sensor (30; 130; 230) is disposed in the tool portion (14; 114; 214) of the tool holder main body (12; 112; 212) so as to be radially between a radially inner wall (18a; 118a; 218a) of a tool receptacle recess (18; 118; 218) of the tool receptacle formation (18; 118; 218) and a radially outer external wall (14a; 114a; 214a) of the tool holder main body (12; 112; 212). - at least one sensor (30, 32, 34, 36; 130, 136; 230, 236) which supplies a detection signal; - a signal transmission device (38; 138; 238) for transmitting a measurement signal from the measuring device (28; 128, 228) to a receiver device which is configured separately from the tool holder (10; 110; 210) and disposed remotely from the latter; - an electric circuit (40; 40a, 40b, 40c) for actuating the sensor (30, 32, 34, 36; 130, 136; 230, 236) and/or for processing the detection signal of the sensor (30, 32, 34, 36; 130, 136; 230, 236) and/or for actuating the signal transmission device (38; 138; 238), which for transmitting signals is connected to the sensor (30, 32, 34, 36; 130, 136; 230, 236) and the signal transmission device (38; 138; 238); and - a power supply device (42; 142) which for transmitting power is connected to the signal transmission device (38; 138; 238) and the electric circuit (40; 40a, 40b, 40c); wherein the tool holder (10; 110; 210) has a tool holder main body (12; 112; 212) which comprises the tool portion (14; 114; 214) and/or the coupling portion (16; 116; 216), wherein at least one component of sensor (30, 32, 34, 36; 130, 136; 230, 236), electric circuit (40; 40a, 40b, 40c) and power supply device (42; 142) is received in a recess (56, 62; 56a, 56b; 156, 162; 256) in the interior of the tool holder main body (12; 112; 212), characterized in that at least one sensor as tool portion sensor (30; 130; 230) is disposed in the tool portion (14; 114; 214) of the tool holder main body (12; 112; 212) so as to be radially between a radially inner wall (18a; 118a; 218a) of a tool receptacle recess (18; 118; 218) of the tool receptacle formation (18; 118; 218) and a radially outer external wall (14a; 114a; 214a) of the tool holder main body (12; 112; 212).