Abstract: Described herein are polymer compositions including a polyphthalamide having a carbon/amide molar ratio greater than 8, a functionalized polyolefin, and a glass fiber, where the weight ratio of the functionalized polyolefin to the total weight of the polyphthalamide and the functionalized polyolefin in the polymer composition is more than 0 and at most 27%. It was surprisingly discovered that the polymer compositions had excellent dielectric performance, acid resistance, and improved mechanical performance, particularly tensile elongation and un-notched Izod impact, relative to corresponding polymer compositions omitting such functionalized polyolefin. Due to the excellent performance, the polymer composition can be desirably incorporated into mobile electronic device components.