Understanding the structure of strained hydrocarbons is important for understanding bonding and controlling reactivity and selectivity. Here we report an experimental and theoretical investigation into the valence electronic structure of bicyclo[2.2.2]octa-2,5-dione (BCOD). A high-resolution electron momentum spectroscopy (EMS) technique was employed to investigate the momentum dependence of specific ionization channels. These experiments were supplemented by an analysis of a measured photoelectron spectrum. Computational chemistry was used to explain the complex electronic structure of BCOD. We analyzed the influence of strain in bridged cyclic diketones by comparison of BCOD with corresponding results from structurally similar molecules to elucidate π/σ through-bond interactions.