This chapter examines the emerging world energy crisis brought on by population growth, escalating energy demands, and CO₂ emissions. Buildings are among the largest energy-consuming sectors and emit a lot of greenhouse gases. Cooling requirements could triple by 2050. Latent Heat Thermal Storage (LHTS), based on the use of Phase Change Materials (PCMs), is suggested as an interesting option to enhance energy efficiency in buildings. The storage and release of heat from PCMs can be quite uniform. This aids in reducing peak thermal loads, smoothing indoor temperatures, and minimizing the size and energy use of HVAC systems. The Chapter covers different LHTS applications, as inclusion in building envelopes, solar energy systems, electronic cooling, and industrial heat recovery. Various types of P CM are presented, including encapsulated and form-stable composites. The chapter concludes with challenges and future research needed to further maximize the PCMs' use for sustainable cooling and energy conservation while reducing environmental concerns.