Deka or DEKA may refer to:
- deka-, an unofficial spelling for deca-, a prefix in the International System of Units
- DEKA (New Zealand), a defunct discount store chain, formerly in New Zealand
- Deka Kamrupi, defense intelligence personnel of Kamarupa (History) kingdom and present Kamrupi surname
- DEKA, a research company located in Manchester, New Hampshire
- Deka, a word in Japanese language holding the meaning police officer
- Deka, a word in Arabic that means "Heartbeat" (Deeqa)
- Ramesh C. Deka, specialist and the Director of All India Institute of Medical Sciences