How many Iranians support the Islamic Republic? In a new working paper, we answer this question using evidence from a nationally representative survey of 2,000 adults in Iran. We use the list experiment, a method for measuring sensitive attitudes. List experiments work by embedding a sensitive item within a list of nonsensitive items and asking respondents how many apply to them—but not which ones—providing a degree of anonymity that reduces the perceived cost of revealing sensitive or socially undesirable attitudes. Measuring regime support in authoritarian contexts is exceedingly difficult. Where dissent is costly, people may publicly express support for a political system they privately reject—a phenomenon known as preference falsification in the study of authoritarian politics. In our study, we find that when asked directly, 57 percent of Iranians say they support the Islamic Republic (between 55 and 59 percent). But on the list experiment, where answers are anonymous, support drops to 47 percent (between 42 and 51 percent).