The development, scope, and application of the highly enantioselective organocatalytic aziridination of α,β‐unsaturated aldehydes is presented. The aminocatalytic azirdination of α,β‐unsaturated aldehydes enables the asymmetric formation of β‐formyl aziridines with up to >19:1 d.r. and 99 % ee. The aminocatalytic aziridination of α‐monosubstituted enals gives access to terminal α‐substituted‐α‐formyl aziridines in high yields and up to 99 % ee. In the case of the organocatalytic aziridination of disubstituted α,β‐unsaturated aldehydes, the transformations were highly diastereo‐ and enantioselective and give nearly enantiomerically pure β‐formyl‐functionalized aziridine products (99 % ee). A highly enantioselective one‐pot cascade sequence based on the combination of asymmetric amine and N‐heterocyclic carbene catalysis (AHCC) is also disclosed. This one‐pot three‐component co‐catalytic transformation between α,β‐unsaturated aldehydes, hydroxylamine derivatives, and alcohols gives the corresponding N‐tert‐butoxycarbonyl and N‐carbobenzyloxy‐protected β‐amino acid esters with ee values ranging from 92–99 %. The mechanisms and stereochemistry of all these catalytic transformations are also discussed.