Multi-mode multi-input multi-output (MIMO) radar sensors are described herein. An example MIMO radar sensor includes a receiver module including an array of receiver antenna elements to receive radar signals and a transmitter module including an array of transmitter antenna elements. Groups of the transmitter antenna elements form transmitter chains. The example MIMO radar sensor further includes a control system to, in a first mode, activate a first set of the transmitter antenna elements of each of the transmitter chains, and, in a second mode, activate a second set of the transmitter antenna elements of each of the transmitter chains, where the second set is larger than the first set. The transmitter antenna elements are arranged such that distances between phase centers of the transmitter chains in the first mode and the second mode are the same.