SDD may refer to:
Computing Software Design Description (IEEE 1016–2009), a standard that specifies the form of the document used to specify system architecture and application design in a software-related project Software Design Document, a written outline of the development of a course or a description of a software product
Solution Deployment Descriptor, a proposed OASIS standard for software deployment, configuration and maintenance Software Design and Development, an HSC subject in NSW that details the basics of designing and developing software applications Syntax-Directed Definition - a context-free grammar with attributes and rules Sentential Decision Diagram, a formalism in knowledge compilation and artificial intelligence Specification-driven development, a software engineering methodology
Finances SDD, for SEPA Direct Debit, a payment system in the Single Euro Payments Area in Europe SDD, ISO code for the Sudanese dinar, the currency of Sudan 1992–2007, now replaced by the Sudanese pound
Science Sulfadimidine, an antibiotic whose abbreviations include SDD Shared delusional disorder, a psychiatric syndrome Silicon drift detector, a p-n junction-based detector for ionizing radiation, such as for X-rays Seasonal deficit disorder, another name for seasonal affective disorder Symmetric diagonally dominant matrix systems in mathematics Selective decontamination of the digestive tract in medicine