Theoretical energy-based conformational analysis of 2-formylselenophene performed at the MP2/6–311G** level together with experimental measurements and SOPPA/aug-cc-pVTZ-J calculations of its ¹³C–¹H, ¹³C–¹³C, and ⁷⁷Se–¹H spin–spin coupling constants showed that this compound predominantly adopts the s-cis conformation. Most of the spin–spin coupling constants under study, especially vicinal ⁷⁷Se–¹H couplings, demonstrate remarkable stereochemical behaviour with respect to the internal rotation of the formyl group, which is of major importance in stereochemical studies of the related selenium-containing compounds.