This article seeks to explain public attitudes to secret surveillance. Secret surveillance, for example wiretapping by intelligence agencies, is a controversial activity that affects fundamental civil liberties in any democratic system. Several large research projects have recently attempted to explain how people form opinions about surveillance in general. Thereby privacy concerns and institutional trust are often highlighted. In this article, we argue that earlier research uses a too narrow definition of attitudes to surveillance and that secret surveillance is particularly sensitive due to its opaque character. We introduce a two-dimensional concept that focuses on rationalistic and emotional responses to surveillance. Drawing on new data from three post-communist societies – Estonia, Poland, and Serbia – we show how institutional trust is mainly responsible for explaining acceptance of secret surveillance, but not how one feels about it. Instead, it is the level of ontological insecurity and privacy concerns that explains this second dimension. The results are theorised and implications for future research are discussed.