Welcome to the IEEE 9th International Workshop on Multidimensional (nD) Systems (nDS15), to be held in Vila Real, Portugal, from the 7th to the 9th of September 2015. The workshop takes place at the University of Trás-os-Montes e Alto Douro, located in the heart of Alto Douro Wine Region, a UNESCO World Heritage Site. The workshop aims to present the most advanced developments in theory as well as in applications of multidimensional systems. Also, provides a privileged forum for discussion between young researchers and specialists in the field. The workshop IEEE nDS15 follows the tradition of its eight successful previous editions, in Lagów 1998, Czocha 2000, Notre Dame 2002, Wuppertal 2005, Aveiro 2007, Thessaloniki 2009, Poitiers 2011 and Erlangen 2013.