Ethanolamine (2-aminoethanol, monoethanolamine, ETA, or MEA) is an organic chemical compound with the formula HOCH
₂CH
₂NH
₂ or C
₂H
₇NO. The molecule is bifunctional, containing both a primary amine and a primary alcohol. Ethanolamine is a colorless, viscous liquid with an odor reminiscent of ammonia. ETA molecules are a component in the formation of cellular membranes and are thus a molecular building block for life. It was thought to exist only on Earth and on certain asteroids, but in 2021 evidence was found that ETA molecules exist in interstellar space.

Derivatives of ethanolamine are widespread in nature; e.g., lipids, as precursor of a variety of N-acylethanolamines (NAEs), that modulate several animal and plant physiological processes such as seed germination, plant–pathogen interactions, chloroplast development and flowering, as well as precursor, combined with arachidonic acid C
₂₀H
₃₂O
₂ 20:4, ω-6), to form the endocannabinoid anandamide (AEA: C
₂₂H
₃₇NO
₂; 20:4, ω-6).

The ethanolamines comprise a group of amino alcohols. A class of antihistamines is identified as ethanolamines, which includes carbinoxamine, clemastine, dimenhydrinate, chlorphenoxamine, diphenhydramine and doxylamine.