LOA may stand for:

• Law of attraction, a belief of New Thought movement
• Leave of absence, a period of time that one must be away from his/her primary job, while maintaining the status of employee.
• Length overall, the maximum length of a vessel's hull measured parallel to the waterline.
• Letter of Agency (also Letter of Authorization), a document authorizing a telecommunications provider to act on a consumer's behalf
• Library of America, an American publisher
• Library Oriented Architecture, a software engineering methodology
• Lines of Action, an abstract-strategy game
• Left occipito-anterior, a cephalic presentation in childbirth

Loa (also spelled Lwa or L'wha) are the spirits of Haitian Vodou and Louisiana Voodoo. They are also referred to as Mystères and the Invisibles and are intermediaries between Bondye (French: Bon Dieu, meaning "good God")—the Supreme Creator, who is distant from the world—and humanity. Unlike saints or angels, however, they are not simply prayed to, they are served. They are each distinct beings with their own personal likes and dislikes, distinct sacred rhythms, songs, dances, ritual symbols, and special modes of service. Contrary to popular belief, the loa are not deities in and of themselves; they are intermediaries for, and dependent on, a distant Bondye.