A nucleating system for a thermoplastic composition that contains a polyarylene sulfide is provided. The nucleating system includes a combination of an inorganic crystalline compound and an aromatic amide oligomer. The present inventors have discovered that the combination of these different types of nucleating agents result in excellent crystallization properties (e.g., rate of crystallization). Due to the improved crystallization rate, the thermoplastic composition can be molded at lower temperatures to still achieve the same degree of crystallization. In addition to minimizing the energy requirements of the molding operating, the use of lower temperatures can also decrease the production of “flash” normally associated with high temperature molding operations. The composition may also possess good viscosity properties that allow it to be readily molded into parts of a variety of different shapes and sizes.