Wai or WAI may refer to:

• Wai, Maharashtra, a town in India
• Koh Wai, also known as Poulo Wai or the Wai Islands, is a group of two small uninhabited islands in the Gulf of Siam, Cambodia
• Wai, a term referring to the walled villages of Hong Kong
• Wai, Māori word for "water" or "river", used as a common prefix in New Zealand place names
• Wa (Japan) (倭), the Cantonese pronunciation of an ancient name of Japan, sometimes transcribed as Wai
• Wai, an alternative name for the Nuristani people, speakers of the Waigali language
• Wai, a form of Thai greeting
• Web Accessibility Initiative, an effort to improve the accessibility of the World Wide Web (WWW or Web) for people with disabilities
• NO WAI, a phrase that is part of the O RLY? Internet meme

The World Wide Web Consortium (W3C)'s Web Accessibility Initiative (WAI) is an effort to improve the accessibility of the World Wide Web (WWW or Web) for people with disabilities. People with disabilities may encounter difficulties when using computers generally, but also on the Web. Since people with disabilities often require non-standard devices and browsers, making websites more accessible also benefits a wide range of user agents and devices, including mobile devices, which have limited resources.