\input zb-basic \input zb-ioport \iteman{io-port 05594547} \itemau{Ardagna, Claudio A.; Cremonini, Marco; De Capitani di Vimercati, Sabrina; Samarati, Pierangela} \itemti{Access control in location-based services.} \itemso{Bettini, Claudio (ed.) et al., Privacy in location-based applications. Research issues and emerging trends. Berlin: Springer (ISBN 978-3-642-03510-4/pbk). Lecture Notes in Computer Science 5599, 106-126 (2009).} \itemab Summary: Recent enhancements in location technologies reliability and precision are fostering the development of a new wave of applications that make use of the location information of users. Such applications introduces new aspects of access control which should be addressed. On the one side, precise location information may play an important role and can be used to develop Location-based Access Control (LBAC) systems that integrate traditional access control mechanisms with conditions based on the physical position of users. On the other side, location information of users can be considered sensitive and access control solutions should be developed to protect it against unauthorized accesses and disclosures. In this chapter, we address these two aspects related to the use and protection of location information, discussing existing solutions, open issues, and some research directions. \itemrv{~} \itemcc{} \itemut{} \itemli{doi:10.1007/978-3-642-03511-1\_5} \end