The effect of various solvents on the morphology of polymethyl methacrylate (PMMA) particles synthesized by spray drying is examined. It is concluded that the product PMMA particles, derived from the PMMA-acetone dilute solution, have a smaller particle size than those from the PMMA-THF dilute solution. This is due to the stronger PMMA-acetone interaction, since acetone is a good solvent for PMMA, while THF is a poor solvent for PMMA. By controlling the temperature of each section of the tube furnace, the heating rate was adjusted so that both solid and hollow particles could be obtained. When water was added to these dilute solutions, porous or honeycomb particles were produced due to the different evaporation rates of solvent and water. This was a result of a large difference in the solubility parameter values between PMMA and solvent. The strong interaction between PMMA and acetone results in the formation of porous particles while the weak interaction between THF and PMMA produced honeycomb structure particles.