In dense environments, parasitic thermal radiation from limited sky views severely restricts traditional omnidirectional radiative cooling. Addressing this, we systematically review directional thermal emission strategies. First, building upon theoretical models, we examine macroscopic geometrical optics strategies utilizing external concentrators and surface morphology engineering. Second, focusing on planar films and metasurfaces, we analyze mechanisms driving broadband and unidirectional emission—including surface wave excitation, ENZ Berreman modes, Fabry−Pérot coupling, and symmetry breaking—alongside dynamic regulation via magnetic deformation, phase−change materials, and hot−carrier effects. Finally, we summarize practical challenges like costly processing and dust−induced weatherability issues. We outline future directions including low−cost manufacturing, self−cleaning designs, and multi-spectral dynamic regulation with solar modulation capabilities, aiming to provide theoretical and technical pathways to enhance the all-scenario potential of radiative cooling.