DDW may refer to:
- DDW, an award winning branding agency in San Francisco, CA
- D.D. Williamson, a global food ingredient company
- Dartmouth Debate Workshop, a summer program
- DDW (language), an Austronesian language spoken in six villages on Dawera and Daweloor islands in South Maluku, Indonesia
- Digestive Disease Week, World Congress for physicians and researchers in the field of gastroenterology, hepatology, endoscopy and gastrointestinal surgery
- Diseases of the Developing World (explanation required)
- Double distilled water, the de facto standard for highly purified laboratory water for biochemistry and trace analysis until combination methods of purification became widespread
- Sailing faster than the wind, also known as "dead downwind" sailing (hence the acronym DDW).
- Dress Down Week, a week where employees does not need to wear formal business clothes. See DDD Dress Down Day. It is usually preceded by a hashtag, ie. #DDW or #DDD. It is a common expression in Budapest and in Poland during the hot summers.