This chapter covers the topic of nano-opto-electro-mechanical systems (NOEMS) and their application in quantum photonic integrated circuits. When reducing the size of optical devices down to the nano-scale, as in nanophotonics and plasmonics, the properties of confined optical waves become increasingly affected by small geometrical variations of the materials. These variations produce a wide range of electro- and opto-mechanical interactions that do not depend on any intrinsic material property and therefore can be operated at cryogenic temperatures and seamlessly integrated in quantum photonic circuits with embedded quantum emitters and single-photon detectors. We discuss the basic principles of operation of NOEMS, the techniques involved in their fabrication, and the functionalities that such devices can provide toward the realization of scalable quantum photonic integrated technologies.