By acting as the interface between digital and physical worlds, wireless sensor networks (WSNs) represent a fundamental building block of the upcoming Internet of Things and a key enabler for Cyber-Physical and Pervasive Computing Systems. Despite the interest raised by this decade-old research topic, the development of WSN software is still carried out in a rather primitive fashion, by building software directly atop the operating system and by relying on an individual's hard-earned programming skills. WSN developers must face not only the functional application requirements but also a number of challenging, non-functional requirements and constraints resulting from scarce resources. The heterogeneity of network nodes, the unpredictable environmental influences, and the large size of the network further add to the difficulties. In the WSN community, there is a growing awareness of the need for methodologies, techniques, and abstractions that simplify development tasks and increase the confidence in the correctness and performance of the resulting software. Software engineering (SE) support is therefore sought, not only to ease the development task but also to make it more reliable, dependable, and repeatable. The three previous editions of the SESENA workshop have made strides in bridging the divide between the SE and WSN communities; nevertheless, open challenges in robust software engineering for WSNs remain. SESENA13 aims to attract researchers belonging to both the SE and WSN communities, not only to exchange recent research results on the topic, but also to stimulate discussion about the core open problems and to define a shared research agenda. The workshop welcomes both research contributions and position statements. The former will foster in-depth technical discussions of novel results with an audience composed of both SE and WSN researchers. The latter will provide the opportunity for presenting open problems, provocative views, or previously unexplored ideas in an informal fashion. To foster discussion, SESENA13 will also host a special "speakers' corner" session composed of impromptu presentations where attendees (including those without accepted papers) will have the opportunity to present their own views in very short statements (e.g., 2-4 minutes).