A large amount of unstructured data is available in software artifacts, such as, documentation, developer discussions, source code, customer support requests, etc. This data contains important information that could be useful for developers in the context of several software engineering tasks. However, due to the large amount of unstructured data available today in software projects, the task of mining it can be challenging. The 6th Workshop on Mining Unstructured Data (MUD 2016) aims to stimulate discussion between researchers in the field about addressing the challenges posed by mining unstructured software data, to encourage cross-fertilization from different research domains, including NLP, IR, Machine Learning, etc. and to document and advance the state of the art of MUD. MUD 2016 is a full-day workshop and will include keynotes, tutorials, paper presentations, posters, and discussion.