MoCS is the first workshop series targeted at cloud computing and Smart City that has been organized in association with the IEEE Symposium on Computers and Communications (ISCC).The long tradition of ISCC as cross-interest forum make it a great place to host the MoCS workshop, whose interests cover the whole virtualization stack, from the kernel up to the application, service and management level. The ambition and mission of MoCS 2017 is to put on the foreground all the issues about management of cloud and Smart City systems at different layer of abstractions, and to bring together different ongoing research efforts related to this field. This year, special focus will be on the challenging management issues related to the delivery of efficient solutions for the processing of real-world Big Data in Smart Cities scenarios. Starting with a rigorous review process and following with the open forum approach, that promotes interaction and discussion between Workshop contributors, we expect the Sixth Workshop on Management of Cloud and Smart city systems (MoCS) to provide relevant and knowledgeable feedback that will assist all authors to significantly enhance the quality of their work.