Biomechanical-to-electrical energy conversion technology rapidly developed with the emergence of nanogenerators (NGs) in 2006, which proves promising in distributed energy management for the Internet of Things, self-powered sensing, and human–computer interaction. Recently, researchers have increasingly integrated inorganic dielectric materials (IDMs) and micro-/nanoarchitectures into various types of NGs (i.e., triboelectric, piezoelectric, and flexoelectric NGs). This strategy significantly enhances the electrical performance, enabling near-theoretical energy harvesting capability and precise multiple physiological information detection. However, because micro-/nanoarchitectured IDMs function differently in each type of NG, numerous studies have focused on a single NG type and lack a unified perspective on their role across all types of biomechanical energy NGs. In this review, from an overall theoretical root of NGs, the performance enhancement mechanisms and effects of designs of IDMs coupling micro-/nanoarchitectures of various kinds of biomechanical energy NGs are systematically summarized. Next, advanced applications in human energy scavenging and physiological signal sensing are delved into. Finally, challenges and rational guidelines for designing future devices are discussed. This work provides researchers with in-depth insight into the development of high-performance personalized high-entropy power supplies and sensor networks via biomechanical-to-electrical energy conversion technologies based on IDMs coupling micro-/nanoarchitectures.