A systematic theoretical study on the pericyclic reactions in acyclic and cyclic ether biofuels was performed. Identified reactions include the classical alcohol formation and a H2 eliminations that was recently shown to play a non negligible role in the thermal decomposition of tetrahydrofuran. Theoretical calculations performed showed negligible H2 elimination in acyclic ethers. In the case of cyclic ethers (tetrahydrofuran and tetrahydropyran) the branching ratio of the unimolecular pericyclic reactions considerably depended on the presence of a lateral alkyl group bonded to the carbon atom in position 2. If an alkyl group is present the alcohol formation was favored through an exo 4-center rearrangement. Meanwhile if no lateral alkyl group is available in position 2 endo alcohol formation and H2 eliminations were equally important. Reaction rate rules were established to include pericyclic decomposition reactions in detailed chemical kinetic models of ether combustion.