High-temperature polymers and their composites are widely used in aerospace applications. Ablative thermal protection systems (TPS) materials are sacrificial materials used to manage the heat shielding in applications, such as space reentry and hypersonic flights. Novel classes of high-temperature polymers have been developed for future space applications. This review will focus on the charring high-temperature polymers with the goal to provide an updated overview of high-temperature resin systems. Several high temperature polymers that have high thermal stability and working temperatures will be discussed in the context of TPS applications. The polymers are divided into thermosets and thermoplastics.