KDA or similar may refer to:

• KDA (DJ), an English house DJ
• Combat Groups of the Working Class (German: ), a paramilitary organization in East Germany
• Kollam Development Authority, an autonomous statutory body responsible for the development of Kollam city, India
• Karachi Development Authority, an urban development organization in Karachi, Pakistan
• Kentucky Distillers' Association, a trade group of distillers that sponsors the Kentucky Bourbon Trail
• Kilodalton (kDa), 1000 unified atomic mass units
• Kongsberg Defence & Aerospace, a Norwegian supplier of defence and space related systems and products
• Kotelawala Defence Academy, a Sri Lankan joint services academy now called Kotelawala Defence University
• Kramer Design Associates, a Canadian graphics design company
• Potassium diisopropylamide, a strong base used in organic chemistry similar to lithium diisopropylamide
• Worimi language, an Australian Aboriginal language

The unified atomic mass unit (symbol: u) or dalton (symbol: Da) is the standard unit that is used for indicating mass on an atomic or molecular scale (atomic mass). One unified atomic mass unit is approximately the mass of one nucleon (either a single proton or neutron) and is numerically equivalent to 1g/mol. It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of . The CIPM has categorised it as a non-SI unit accepted for use with the SI, and whose value in SI units must be obtained experimentally.

The Combat Groups of the Working Class (German: Kampfgruppen der Arbeiterklasse, KdA) was a paramilitary organization in East Germany, founded in 1953 and abolished in 1990.