IT strategy development in organisations is a complex task for which there is an immediate need for methodological support to be able to make satisfying decisions. Group Decision Support Systems (GDSS) is one line of supporting the process of group decision making and supporting IT strategy development. This paper discusses the features of GDSSs in terms of a broad definition, and a focus on how it supports and makes impact on group decision making. For illustrating reasons, an existing GDSS is presented: the Strategic ADvisor, STRAD. STRAD is presented and it is showed how this GDSs can be used to support development of organisational IT strategies.