DDA may stand for:
- Danish Design Award
- Delhi Development Authority, the Planning Agency for Delhi, the capital of India.
- Dda (DNA-dependent ATPase), a DNA helicase.
- Demand deposit account, the classification that checking accounts fall into.
- Depletion Depreciation Amortization, components of the financial report known as Income Statement ; often combined & summarized on a single line labelled as DDA
- MTU Detroit Diesel Australia, a diesel engine manufacturer in Australia and joint venture between Tognum and Daimler AG.
- Deputy District Attorney
- Disability Discrimination Act 1992, Australian legislation relating to disability discrimination.
- Disability Discrimination Act 1995, UK legislation relating to disability discrimination.
- Discontinuous Deformation Analysis, an analysis procedure used in physics and engineering.
- Discrete Dipole Approximation, method for computing scattering of radiation by particles of arbitrary shape.
- Digital Differential Analyzer, a method of drawing lines on a computer screen, such as Bresenham's line algorithm. Also used in CNC (Computer Numerical Control) systems for manufacturing.
- Digital Differential Analyzer, a digital implementation of a Differential Analyzer.
- The Division on Dynamical Astronomy, a branch of the American Astronomical Society
- Defence Diversification Agency, an executive agency of the UK Ministry of Defence.
- Dog Day Afternoon, a 1975 film starring Al Pacino.
- Doha Development Agenda of the World Trade Organization
- Downtown Development Authority in the United States; see Main Street Programs in the United States
- Dutch Dakota Association, a Dutch organisation dedicated to preserving and operating classic aircraft.
- Dynamic game difficulty balancing, also known as Dynamic Difficulty Adjustment, the method of automatically adjusting video game difficulty based on player ability.
- Don't Do Anything in the game N.
- Damn Dirty Ape Planet of the Apes, 1968.