A polyester composition, suitable for use as a dispersant in lubricating oils, is disclosed. The polyester composition is prepared by reacting (a) an acylating agent selected from an aliphatic-substituted succinic acylating agent, an aromatic polycarboxylic acylating agent, and combinations thereof; and (b) a hydroxyalkyl-substituted tertiary amine compound of the following structure: wherein R′ is a C1-24 aliphatic group; R in each of the x (RO), y (RO) and z (RO) groups is independently C2-4 alkylene; x+y is in a range of 2 to 7; and z is in a range of 1 to 5.