The Generic Conspiracist Beliefs Scale (GCB-15) is a reliable and valid measure of conspiracist ideation, but it is also inefficient. At 15 items, the GCB-15 can take upwards of four minutes to complete. Here we introduce the GCB-5—a 5-item, short form of the GCB-15. Across five studies, we use self- and informant-report methods to demonstrate that the GCB-5 is a reliable, criterion-valid, and construct-valid measure of conspiracist ideation. In the final study, we further provide evidence that the GCB-5 has promise for addressing novel research questions. Specifically, we show that people high in conspiracist ideation—as assessed by the GCB-5—are more accepting of the use of nuclear weapons and other forms of so-called “virtuous violence” (e.g., anti-abortion legislation).