Opium or breadseed poppy (Papaver somniferum L.; Papaveraceae) is planted as an ornamental and widely cultivated for diverse uses, but especially as a source of alkaloids such as codeine and morphine. Despite a mature knowledge of the plant's biochemistry, its insect fauna is not well known, except for species of economic importance. In a South Carolina botanical garden, the Heteroptera associated with capsules (fruits) of P. somniferum were observed periodically from 2017 to 2019. Adults of the polyphagous coreid Leptoglossus phyllopus (L.) colonized poppies in mid- to late May and mated on immature (and later on ripened) capsules. As capsules mature, their encircling apical pores open to allow seeds to disperse, which also permitted early instars of the coreid to enter. Larger holes in the parchment-like capsule walls (pericarp), which might be made by downy woodpeckers, facilitated entry by later instars. Nymphs, typically late instars, and adults on the surface of immature capsules were observed with their stylets inserted in the pericarp, suggesting that they feed on developing seeds. It is not known if nymphs with stylets inserted in the pericarp of mature capsules, or those inside capsules, are able to feed on mature seeds. Nymphs of the rhyparochromid seed bug Neopamera bilobata (Say) fed only within dry capsules where they apparently developed on ripened seeds. Capsules serve as a food source for poppy-associated bugs, but those that enter via pores or larger openings on the pericarp might minimize desiccation and be more protected from rain, wind, and natural enemies than if they remained exposed on the surface. Nymphs and adults of the pentatomid Euschistus servus (Say) and adults of the rhyparochromid Atrazonotus umbrosus (Distant) also were observed on or in capsules, but their relationship to P. somniferum was not determined.