Planning is a basic organizational decision-making activity often requiring the judgement and expertise of a group of organization members. Computer and communications support for the planning process can help individuals and groups who may have different perspectives and priorities, to communicate and Coordinate their activities. This article examines how groups organize their planning and decision-making activities in a number of application areas, and identifies their requirements in terms of communication structures and online information systems capabilities. Examples are given from engineering projects, computer projects, scientific communities, company planning, and crisis management. The applicability of a distributed decision-making approach to organizing information systems support is assessed as a way of meeting these requirements.