Diethyl tartrate is an organic compound with the formula (HOCHCO2Et)2 (Et = ethyl).

They are the ethyl esters of the respective R,R-, S,S-, and R,S-tartaric acids.

The R,R- and S,S- isomers are enantiomeric, being mirror images.

In the Sharpless epoxidation, diethyl tartrate and titanium isopropoxide form a chiral catalyst in situ.

[1] The TADDOL ligand scaffold is produced from diethyl tartrate.