亚磷酸三乙酯是一种具有分子式P(OCH₂CH₃)₃的有机磷化合物，常简写为P(OEt)₃。它性状为无色液体，常用于有机金属化学中的配体，以及有机合成中的试剂。其分子形态为锥形，三价磷原子连接于三个乙氧基上。

亚磷酸三乙酯可通过三氯化磷和乙醇在碱的存在下反应进行制备：

许多类似的化合物都可通过这种方法制备，亚磷酸三异丙酯也可如使用这种方法制备。（b.p. 43.5 °C/1.0 mm; CAS# 116-17-6）。

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 P 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.