Tetrabutylammonium hydroxide is the chemical compound with the formula (C4H9)4NOH, abbreviated Bu4NOH with the acronym TBAOH or TBAH.

Relative to more conventional inorganic bases, such as KOH and NaOH, Bu4NOH is more soluble in organic solvents.

[1] Solutions of Bu4NOH are usually prepared in situ from butylammonium halides, Bu4NX, for example by reacting them with silver oxide or using an ion exchange resin.

[1] Treatment of Bu4NOH with a wide range of acids gives water and the other tetrabutylammonium salts: Bu4NOH is a strong base that is used often under phase-transfer conditions to effect alkylations and deprotonations.

[1] Bu4NOH can be neutralized with a variety of mineral acids to give lipophilic salts of the conjugate base.