"Software Knowledge" – in short SKY – means that software in its higher abstraction levels is a new kind of knowledge, Runnable knowledge as an end goal. Thus, the classes and relationships of a software system design are easily viewed as classes and relationships in a knowledge ontology. For further details visit SoftwareKnowledge.org. The main theme of the SKY2015 Workshop is Big Data in Software Knowledge. The exponential growth and availability of data, both structured and unstructured is the main focus point for SKY2015. Time is ripe to investigate the promising implications of Big Data and new ideas on how to deal with huge amounts of Knowledge in the System Environments. The Workshop main objective is to discuss and propose practical tools and scientific approaches to deal not only with experimental and laboratory research, but to facilitate the management of Big Data for industrial systems.