A temperature compensated Micro Electro Mechanical (MEMS) oscillator is provided. The oscillator includes a MEMS resonator group, a heating device, a connection body, and a controller. The MEMS resonator group includes a first MEMS resonator and a second MEMS resonator. The first MEMS resonator is configured to output a main oscillation frequency. The second MEMS resonator is configured to output an auxiliary oscillation frequency according to a temperature of the second MEMS resonator. The heating device is configured to increase a temperature of the MEMS resonator group. The connection body is connected between the MEMS resonator group and the heating device to transmit heat from the heating device to the MEMS resonator group, and configured to electrically isolate the MEMS resonator group from the heating device. The controller is configured to control the heating device according to a difference between the main oscillation frequency and the auxiliary oscillation frequency.