GDD may mean: Game design document, a design document specific to video games. Gaseous detection device, a technology used with some electron microscopes and similar instruments Geographically Distributed Development Glaucoma drainage device Global Data Dictionary Global Drug Development Global developmental delay, a childhood medical disorder Goal-Directed Design, a user interface design method developed by Alan Cooper Group delay dispersion (Group velocity dispersion), effect of a medium on an optical signal Google Developer Day, Google promotional events for developers Great Dragon's Dale, a Russian-language video gaming magazine Green Degree Directory Growing degree-day, a unit for measuring climatic warmth over a period of time