Mars and the Moon are two representative weakly magnetized bodies in the solar system lacking a global dipole magnetic field. Their space environments are directly exposed to solar wind perturbations, giving rise to plasma wave dynamics and kinetic processes that differ fundamentally from those within Earth's magnetosphere. In recent years, benefiting from extensive in-situ observational data accumulated by deep-space missions including MGS, Mars Express, MAVEN, Tianwen-1, Lunar Prospector, Kaguya, and ARTEMIS, breakthrough progress has been achieved in characterizing low-frequency and very-low-frequency electromagnetic and electrostatic waves in the Martian and lunar space environments.

Within the framework of comparative planetology, this paper systematically reviews the current state of research on typical plasma waves at Mars and the Moon. For Mars, we examine the spatiotemporal distributions and excitation mechanisms of multiple wave types, including proton cyclotron waves, 1 Hz waves, 30 s waves, and 3 s waves in the upstream foreshock; Alfvén waves, solar-wind-origin and locally generated magnetosonic waves, whistler-mode waves, and mirror-mode waves in the magnetosheath and induced magnetosphere; as well as sawtooth-like boundary perturbations associated with Kelvin–Helmholtz instability. Particular emphasis is placed on their critical roles in electron pitch-angle scattering, ion heating, cross-boundary energy transport, and atmospheric escape. For the Moon, we review diverse electromagnetic and electrostatic wave populations driven by surface absorption and reflection, magnetic anomaly deflection, and wake potential structures, encompassing narrowband ULF waves, broadband whistler-mode waves, 1 Hz and 100 Hz narrowband whistler-mode waves, electron cyclotron harmonics, broadband electrostatic noise, Langmuir waves, and wake precursor waves. The physical picture in which particle velocity distribution function reconstruction serves as the primary driver of wave excitation is highlighted.

Building upon this comparative synthesis, we discuss the common physical principles governing plasma wave processes at weakly magnetized bodies, along with key unresolved challenges. Future directions including multi-spacecraft coordinated observations, high-time-resolution particle distribution measurements, kinetic numerical simulations, and the establishment of a unified comparative planetology framework are also outlined. This review provides a valuable reference for understanding solar wind interactions with weakly magnetized bodies and offers a theoretical basis for scientific objective formulation and payload design in future deep-space exploration missions.