Abstract: Recent research on conspiracy theories, in philosophy as well as in other fields, has tended to focus on beliefs that are (from a ‘mainstream’ perspective at least) outlandish, absurd and patently false: QAnon, Covid-19 vaccines containing traceable microchips, 9/11 as an ‘inside job’. What is arguably conspicuously absent in much of this literature is a parallel reflection on the existence of real conspiracies. To fill this lacuna, I adopt an environmental epistemic perspective—where agents are considered in the broader context of epistemic environments and where attentional networks and perceptions of trustworthiness significantly influence the uptake of beliefs in an epistemic community—to explain both how conspiratorial beliefs spread and how real conspiracies can be hidden from the public. I argue that these two kinds of processes are each other’s counterparts, structurally having much in common. In both cases, epistemic environments can be ‘engineered’ so as to foster the spread of certain beliefs (regardless of their truth or plausibility), or alternatively so as to hide certain facts that conspirators do not want to become widely known.