Tetrabutylammonium hydroxide is widely used as a phase transfer catalyst in organic synthesis, facilitating reactions between compounds in different phases, such as aqueous and organic layers. It is particularly effective in nucleophilic substitution reactions, where it enhances the transfer of anions to organic substrates. In analytical chemistry, it serves as an ion-pairing agent in high-performance liquid chromatography (HPLC) to improve the separation of ionic compounds. Additionally, it is employed in the preparation of quaternary ammonium salts and in the synthesis of pharmaceuticals and fine chemicals. Its strong basicity also makes it useful in deprotonation reactions and as a titrant in non-aqueous titrations.

In the electronics industry, it is commonly used in the production of printed circuit boards (PCBs) for cleaning and surface conditioning prior to coating with other chemicals. It is also applied in semiconductor manufacturing and nanomaterial production to control the growth of nanostructures and enhance electrical and optical properties of materials.