Zai

Zai may refer to:
 * Democratic Republic of the Congo, formerly Zaire, ongoing UNDP code ZAI
 * Zaï, an off season farming technique to collect water and nutrients from compost, to restore degraded drylands and increase soil fertility
 * Zai (surname) (宰), a Chinese surname
 * Zai (tribe), Pashtun tribes
 * Zai, Palghar, a village in Maharashtra, India
 * Zväz autorov a interprétov populárnej hudby (Union of Authors and Performers, ZAI), a presenter of the ZAI Awards
 * Zaire, a former state in Africa
 * Zayin, a letter of many Semitic abjads
 * Isthmus Zapotec (ISO 639-3: zai), a Zapotecan language of Mexico

Given names

 * Li Zai (died 1343), Chinese painter
 * Wang Zai, Chinese general of the Tang Dynasty
 * Yuan Zai (died 777), Chinese noble, Chancellor of the Tang Dynasty
 * Zhang Zai (1020–1077), Chinese philosopher and cosmologist
 * Zai Bennett, Television executive
 * Zai Fundo (1899–1944), Albanian journalist and writer