TDW may refer to one of the following:
TDW (Gesellschaft für verteidigungstechnische Wirksysteme), a European weapons manufacturer; Three-Day Week, one of several measures introduced in the United Kingdom by the Conservative Government of 1970–1974 to help conserve electricity; The Dark World, a science fantasy novel by Henry Kuttner; Tidewater Inc. (NYSE:TDW), an international petroleum service company; The Daily WTF, a humorous blog on software engineering disasters; Borland Turbo Debugger for Windows 3 Tradewind Airport, IATA code TDW