Abstract Energy harvesters are being developed to meet the power requirements of the wireless sensor networks (WSNs) and remote monitoring devices to enhance the lifetime and limitations of conventional batteries. There are many different mechanisms that can be utilized to scavenge the energy from the environment, including piezoelectric, magnetoelectric, inductive, photovoltaic, electrostatic, thermoelectric, and dielectric. Among the various possibilities for vibration and magnetic field energy harvesting, magnetoelectric (ME) composites combining the piezoelectric and magnetostrictive phase provide great potential. In this chapter, we will systematically describe the development of ME composites and their application as magnetoelectric energy harvesters. A self-biased magnetoelectric composite that can generate voltage in the absence of direct current (DC) bias will be discussed in detail. The principles behind the design to harvest energy from mechanical vibrations and magnetic fields, individually or simultaneously, will be illustrated. Other considerations, such as the arc-based concept that ensures low resonance frequency across different length scales while providing the wideband, will also be discussed.