Abstract: Thermoplastic compositions comprising a bulk polymer, an additive, and a compatibilizer/emulsifier/surfactant (CES) are described. The bulk polymer comprises an alkylene terephthalate or naphthalate polyester such as polyethylene terephthalate. The additive comprises an amorphous or substantially amorphous co-polymer of ethylene and a co-monomer that forms polar portions, such as methylacrylate, butylacrylate, ethylacrylate, or ethylhexyl methacrylate. The CES comprises a co-polymer or terpolymer of ethylene and a glycidyl acrylate or maleic anhydride, and optionally an acrylate such as methylacrylate, ethylacrylate, propylacrylate, butylacrylate, ethylhexyl acrylate, or mixtures thereof. The thermoplastic compositions of the present invention exhibit improved molding properties, high dimensional stability, high temperature resistance, and are particularly useful in food-grade applications such as dual-ovenable containers.