Hybrid nanoparticles combine two or more disparate materials on the same nanosystem and represent a powerful approach for achieving advanced materials with multiple functionalities stemming from the unusual materials combinations. This review focuses on recent advances in the area of semiconductor–metal hybrid nanoparticles. Synthesis approaches offering high degree of control over the number of components, their compositions, shapes, and interfacial characteristics are discussed, including examples of advanced architectures. Progress in hybrid nanoscale inorganic cage structures prepared by a selective edge growth mechanism of the metal onto the semiconductor nanocrystal is also presented. The combined and often synergistic properties of the hybrid nanoparticles are described with emphasis on optical properties, electronic structure, electrical characteristics, and light induced charge separation effects. Progress toward the application of hybrid nanoparticles in photocatalysis is overviewed. We conclude with a summary and point out some challenges for further development and understanding of semiconductor–metal hybrid nanoparticles. This progress shows promise for application of hybrid nanoparticles in photocatalysis, catalysis, optical components, and electronic devices.