Reaction enthalpies for hydrogen transfer reactions provide a quantitative basis for the definition of the stability of C‐, S‐, O‐, N‐, and B‐centered radicals. The radical stabilization energies (RSEs) obtained in this way reflect the influence of the substitution pattern on the unpaired spin as well as ground state effects in the respective closed shell parent systems. The combination of theoretically calculated RSEs with experimentally measured bond dissociation energy (BDE) data allows for the construction of global stability scales for radicals of different type and thus the opportunity to predict reaction energies for a wide range of hydrogen transfer reactions.