This chapter provides a comprehensive overview about design, optimization, fabrication, and application of MEMS vibration energy harvesters. The content is structured to initially introduce various transduction methods applicable at the MEMS/NEMS scale for converting vibration into electricity. Thereafter, microfabrication methods for fabrication of each standalone transduction method are discussed. The inherent shortcomings of each group of MEMS harvesters such as narrow bandwidth or low power efficiency are explained in detail and up to date employed proposed solutions to overcome these obstacles are highlighted. In addition, the chapter delves into the crucial aspect of MEMS harvesters, power management systems, where various circuitry architectures designed to rectify, regulate, and store the harvested energy are studied. To provide practical relevance of the MEMS harvesters, their application in diverse fields such as Internet of Things (IoT), and wearable devices is explained.