The present disclosure provides a crystalline form of grapiprant selected fromthe groupconsisting of Form X, Form X2, Form X3, Form F, Form K, Form L, Form M, andForm N. Alsoprovided is a pharmaceutical composition, the composition comprising at leastone crystallineform of grapiprant, and at least one pharmaceutically acceptable excipient,wherein thecrystalline form of grapiprant is selected from the group consisting of FormX, Form X2, FormX3, Form F, Form K, Form L, Form M, and Form N. Other aspects of thedisclosure provide aprocess for preparing a substantially pure crystalline Form A of grapiprant.The processcomprises contacting grapiprant at ambient temperature with a solventcomprisingdichloromethane and acetone to form a saturated or a near saturated solution.Crystals of thesubstantially pure crystalline Form A of grapiprant are formed.