These proceedings contain the papers presented at the 3rd International S- posium on Location- and Context-Awareness in September of 2007. Computing has become mobile, wireless, and portable. The rangeof contexts encountered while sitting at a desk working on a computer is very limited c- pared to the large variety of situations experienced away from the desktop. For computing to be relevantanduseful in these emergingsituations, computers will need to take advantage of users location, activities, goals, abilities, preferences, interruptibility, affordances, and surroundings. With this contextual awareness, we can expect computers to deliver information, services, and entertainment in a way that maximizes convenience and minimizes intrusion. This symposium presented research aimed at sensing, inferring, and using location and context data in ways that help the user. Developing awareness - volvesresearchin sensing, inference, data representation,and design. We sought technical papers describing original, previously unpublished research results - cluding: – Sensing location and context – Inference techniques for context from low-level sensor data – Privacy and sharing of location and context information – User studies of location- and context-aware systems Our call for papers resulted in 55 submissions, each of which was assigned to members of our Program Committee. After reviews and e-mail discussions, we selected 17 papers for publication in these proceedings. We extend a sincere thank you to all the authors who submitted papers, to the 33 hard-working members of our Program Committee, and to our external reviewers.