Ex-partner stalkers are more persistent and more likely to use violence than stranger or acquaintance stalkers, but are less likely to incur criminal convictions. The current research explores the influence of prior relationship on mock jury deliberations and verdict decisions in relation to a hypothetical case tried under the Protection from Harassment Act (PfHA) 1997. Six mock juries were presented with one of three versions of a hypothetical case summary and were asked to provide unanimous verdicts concerning whether the defendant was guilty of an offence. Both mock juries in the stranger condition reached unanimous guilty verdicts, while neither mock jury in the ex-partner condition was able to agree a unanimous verdict. It was apparent that the differing perceptions of the defendant’s and plaintiff’s behaviour varied as a function of their prior relationship.