An actuating device for the selection and/or actuation of a gear ratio of a motor vehicle transmission and for engaging and/or disengaging a motor vehicle clutch, having a drive motor which drives a drive shaft that is connectible non-rotatingly to a gear selector drum of a transmission actuating device to move and/or rotate the gear selector drum, the gear selector drum also being connected to a transmission, and having a clutch actuating device which controls a release bearing of a clutch, wherein a master cylinder of the clutch actuating device, which is connected hydraulically to a slave cylinder that moves the release bearing, is actuatable depending on the position of the drive shaft, wherein an actuating segment which protrudes in the radial direction from the drive shaft is connected non-rotatingly to the drive shaft and the actuating segment actuates the master cylinder when the drive shaft is rotated in at least one direction of rotation, as well as to a drivetrain having such an actuating device is provided.