* Evaporation
* Sublimation
* Cracking of alkanes
* Thermal decomposition
* Hydrolysis
* Nucleosynthesis of elements heavier than nickel in stellar cores
* High-energy neutrons can produce tritium from lithium-7 in an endothermic process, consuming 2.466 MeV. This was discovered when the 1954 Castle Bravo nuclear test produced an unexpectedly high yield.
* Nuclear fusion of elements heavier than iron in supernovae
*Dissolving together barium hydroxide and ammonium chloride
*Dissolving together citric acid and baking soda