Rai may refer to:

• Rai (Indian), a number of related Indian legal terms and titles, with various meanings and compound forms
• Aishwarya Rai, an Indian Bollywood actress
• Rai (ethnic group), an ethnolinguistic group of Nepal
• Rai language - see Dhanwar language
• Raï, a form of folk music, originated in Oran, Algeria, from Bedouin shepherds
• Ray, Iran
• Raí, Brazilian football (soccer) player
• Rai (book), a book by Kensaku Shimaki
• Rai (money) a kind of stone money used in Yap (Caroline Islands)
• Rai, Orne, a commune of the Orne département, in France
• Rai Bakuoh, one of the characters from the fighting game Waku Waku 7
• Rai University, a university in India.
• Rai, the word for paradise in Slavic languages
• a traditional Thai unit of area, equaling 1600 m²
• Rai (comics), a fictional character from Valiant Comics.
• Raidiese F. Branstein, a fictional character from Super Robot Taisen
• Thunder in Japanese.
• Rai, a surname of Tulu speaking Shetty or Bunt community of Mangalore.

The acronym RAI refers to:

• RAI, Radio Audizioni Italiane, Italian public broadasting