In this paper, we present an epistemic logic approach to the compositionality of several privacy-related informationhiding/disclosure properties. The properties considered here are anonymity, privacy, onymity, and identity. Our initial observation reveals that anonymity and privacy are not necessarily sequentially compositional; this means that even though a system comprising several sequential phases satisfies a certain unlinkability property in each phase, the entire system does not always enjoy a desired unlinkability property. We show that the compositionality can be guaranteed provided that the phases of the system satisfy what we call the independence assumptions. More specifically, we develop a series of theoretical case studies of what assumptions are sufficient to guarantee the sequential compositionality of various degrees of anonymity, privacy, onymity, and/or identity properties. Similar results for parallel composition are also discussed.We briefly review epistemic logic for multiagent systems. Notions and terminologies are borrowed from [9,12].A multiagent system consists of n agents with their local states and develops over time. We assume that an agent's local state encapsulates all the information to which the agent has access. Let I = {i 1, . . . , in} be the set of n agents. A global state is defined as the tuple (s i 1 , . . . , si n ) with all local states from i 1 to in. A run is a function from time, ranging over the natural numbers, to global states. A point is a pair