This article describes the processing of polyphenylsulfone (PPSU) into microspheres via the physicochemical method called spray drying. These microspheres have the potential to be used as build material for selective laser sintering provided they have spherical morphology and have a mean particle size in the range of 45-95 micrometer. The effects of the different processing parameters on these two response factors have been investigated in spray drying of PPSU by Design of Experiment. A plot is predicted in which size and morphology are optimized and combined in order to find the ideal parameter set for production. The effect of polymer concentration, solution feed rate, atomization flow rate, inlet temperature and polymer grade was optimized using a five-factor and two-level factorial design with center points. Experimental validation is performed to certify the conclusion. The particles were characterized by SEM, DSC and GPC. Particles showed no significant degradation due to processing and had overall good morphology.