N-Methyldiethanolamine is an organic compound with the chemical formula C5H13NO2. It appears as a colorless or deep yellow oily liquid, miscible with water and alcohols. It is primarily used as an emulsifier, acid gas absorbent, acid-base controller, and polyurethane foam catalyst. It also serves as an intermediate in the production of antitumor drugs such as nitrogen mustard.

It is widely used in the desulfurization and purification of oilfield gas and coal gas as an emulsifier and acid gas absorbent, acid-base controller, and polyurethane foam catalyst. In the presence of activators, it can remove carbon dioxide from synthetic ammonia. Additionally, it can be used as an intermediate for insecticides, emulsifiers, textile auxiliaries, antitumor drugs like nitrogen mustard, a catalyst for amino carbamate coatings, a fiber auxiliary, and also as a drying accelerator in paints.