MEMS sensors and actuators are enabling components for smartphones, AR/VR, and wearable electronics. MEMS packaging is recognized as one of the most critical activities to design and manufacture reliable MEMS. A unique challenge to MEMS packaging is how to protect moving MEMS devices during manufacturing and operation. With the introduction of wafer level capping and encapsulation processes, this barrier is removed successfully. In addition, MEMS devices should be integrated with their electronic chips with the smallest footprint possible. As a result, 3D packaging is applied to connect the devices vertically for the most effective integration. Such 3D packaging also paves the way for further heterogenous integration of MEMS devices, electronics, and other functional devices. This book consists of chapters written by leaders developing products in a MEMS industrial setting and faculty members conducting research in an academic setting. After an introduction chapter, the practical issues are covered: through-silicon vias (TSVs), vertical interconnects, wafer level packaging, motion sensor-to-CMOS bonding, and use of printed circuit board technology to fabricate MEMS. These chapters are written by leaders developing MEMS products. Then, fundamental issues are discussed, topics including encapsulation of MEMS, heterogenous integration, microfluidics, solder bonding, localized sealing, microsprings, and reliability.