Although much has recently been published concerning methods for the weight prediction of individual structural components, it is some considerable time since a review of the subject as a whole has appeared. This note is an attempt to remedy the situation, the scope of the work not being limited to aircraft structures but including also equipment and systems. Various stages in the design process are considered, commencing with simple formulae suitable for use in the operations system stage, passing through the more detailed project stage and finally recommending methods suitable for weight prediction as the design becomes established. In some instances the suggested formulae are well known, but an effort has been made to utilise the latest available information in bringing techniques up to date and where possible to fill in gaps, particularly with respect to equipment and systems.