EWiLi's two first editions were dedicated to the Embedded Linux operating system which has progressively constituted a strong alternative to proprietary and/or commercial solutions in embedded systems, whether it is deeply embedded or not, and this for many application domains, such as multimedia, telephony, and transport. The steering committee has considered requests from potential contributors and decided to extend the scope of the workshop to all embedded operating systems. We believe that this new perimeter will make the workshop even richer. EWiLi, the embedded operating system workshop, aims at presenting state-of-the-art research, experimentations, significant and original realizations that focus on the design and implementation of embedded operating systems in both academic and industrial worlds. 2013's edition was hosted at the ENSEEIHT engineering school in Toulouse and was jointly organized with ETR the French summer school on real-time systems. Indeed, Toulouse is a leading place in France and Europe for embedded and real-time systems design for many domains like aeronautics, and transportation in general. EWiLi workshop featured two distinguished keynote speakers, delivering state-of-the-art presentations on topics related to real-time and embedded operating systems: Dr. Joel Sherrill Director of Research and Development OAR Corporation, USA, with a talk on "Scheduling and Thread Management with RTEMS". Dr. Robert Davis Senior Research Fellow in the Real-Time Systems Research Group, University of York, and a Director of Rapita Systems Ltd., UK, with a talk on: "Uniprocessor Real-Time Scheduling" In addition to the keynotes, three sessions were programmed with three regular paper presentations each: "RTOS scheduling", "RTOS design and implementation" and "Performance and energy issues for embedded operating systems". Accepted regular papers were submitted from 8 different countries. The EWiLi Program Committee worked hard to provide high quality reviews for each paper (at least 3 reviews per paper). The 3rd edition of EWiLi was made possible thanks to the support of different institutions including: AdaCore, Captronic, Lab-STICC laboratory, University of Western Brittany (UBO, Brest). ACM SIGBED Reviews and ACM SIGOPS French Chapter (ASF) have also strongly contributed in making the event successful. We would like to thank all members of the Program Committee for their valuable efforts for prompt and high quality reviews, advices, and various help they provided to make that event successful. Finally, we also would like to thank all the authors of the submitted papers and all the participants who contributed in making EWiLi an exciting forum for researchers and practitioners. We hope they appreciated the program of the 3rd edition of the EWiLi workshop. July 2013 EWiLi chairs Jalil Boukhobza Jean-Philippe Diguet Pierre Ficheux Frank Singhoff