Di-Octyl phthalate ( DOP) is an organic compound with the formula C6H4(CO2C8H17)2.

DOP is the most common member of the class of phthalates, which are used as plasticizers.

It is the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colorless viscous liquid is soluble in oil, but not in water.