There is a widespread assumption by academics and commentators that negative public attitudes to the benefits system are due to 'myths' held by the British public. However, there is little research on whether the public believe these 'myths', nor critical scrutiny of benefit 'truths'. This article therefore investigates what British people believe about the benefits system, and the extent to which these beliefs can be regarded as correct. To do this, we use 46 measures from 18 datasets (including British Social Attitudes, the European Social Survey, Eurobarometer, and surveys by YouGov and Ipsos MORI made available for academic study for the first time), and compare these perceptions to true figures obtained from a variety of sources. We find thatagainst expectationsthere are some areas where the public are (on average) relatively accurate (e.g. the share of the population who currently claim out-of-work benefits). Yet overall, our evidence shows that the British public have low levels of understanding of the benefits system, primarily in ways that seem likely to undermine public support. People wildly overestimate unemployment benefits compared to pensions, the value of unemployment benefits, and misperceive trends in claims. While it is difficult to know the true level of benefit fraud exactly, the public overestimate fraud compared to any reasonable figure. We conclude by discussing the implications for both understanding and changing attitudes towards benefits.