An online experiment (n = 1,897) was carried out to understand how data disclosure practices in ubiquitous surveillance affect users’ privacy concerns. Information about the identity and intentions of a data collector was manipulated in hypothetical surveillance scenarios. Privacy concerns were found to differ across the scenarios and moderated by knowledge about the collector’s identity and intentions. Knowledge about intentions exhibited a stronger effect. When no information about intentions was disclosed, the respondents postulated negative intentions. A positive effect was found for disclosing neutral intentions of an organization or unknown data collector, but not for a private data collector. The findings underline the importance of disclosing intentions of data use to users in an easily understandable manner.