This paper addresses issues regarding perceptions of surveillance technologies in Europe. It analyses existing studies in order to explore how perceptions of surveillance affect and are affected by the negative effects of surveillance and how perceptions and effectiveness of surveillance technologies relate to each other. The paper identifies 12 negative effects of surveillance including, among others, privacy intrusion, the chilling effect and social exclusion, and classifies them into three groups. It further illustrates the different ways in which perceptions and effectiveness of surveillance interact with each other, distinguishing between perceived security and perceived effectiveness. Finally, the paper advances a methodology to take into account perception issues when designing new surveillance technologies. By doing so, it rejects manipulative measures aiming at improving perceptions only and suggests measures that address the background conditions affecting perceptions.