Public opinion research on immigration attitudes has largely overlooked the question of how survey respondents understand the term “immigrants”. This paper investigates latent perceptions of immigrants, termed “imagined immigration”, among members of the British public. Using novel survey data, I examine who members of the British public have in mind when they think of “immigrants”. I find that public perceptions of immigration diverge significantly from the set of people identified as immigrants in government statistics and targeted by restrictionist policies. In particular, public perceptions focus on asylum seekers and permanent arrivals, while mostly ignoring international students, the largest group of immigrants to Britain and a target of new restrictive immigration policies. I also show that many common perceptions of “imagined immigration” are strongly associated with individual preferences for reduced immigration, suggesting that imagined immigration should be considered in future research as a possible determinant of anti-immigration policy preferences.