Triethylphosphite is an organophosphorus compound with the formula P(OCH2CH3)3, often abbreviated P(OEt)3. This colorless liquid is used as a ligand in organometallic chemistry and as a reagent in organic synthesis, and has a 31P NMR signal at around +139 ppm with reference to a phosphoric acid standard. The molecule features a pyramidal phosphorus(III) center bound to three ethoxide groups.