A quetiapine fumarate composition for oral administration is provided comprising a pharmaceutically acceptable salt or solvate of quetiapine existing as a suspension in an aqueous carrier agent. The inventive liquid formulation demonstrates high bioavailability consistent with approved dosage forms, low agglomeration, reduced content of excipients commonly used in solid oral dosage forms and extended shelf life stability. Also provided is a method of manufacturing a liquid quetiapine suspension composition for oral administration and methods of administering therapeutically effective dosages of an oral liquid quetiapine suspension composition to patients in need thereof.