Development of orbital inflammatory granulation in pregnant patients as an orbital complication of acute sinusitis is extremely rare. Herein, we describe the case of a patient with a complication of acute sinusitis that mimicked orbital tumors. The patient presented with left orbital protrusion. Magnetic resonance imaging revealed pansinusitis with a well-defined mass lesion in the extraconal space of the left orbit. Endoscopic endonasal sphenoethmoidectomy and orbital decompression were performed. Histopatological examination revealed acute inflammatory granulation tissue. To the best of our knowledge, this is the first report to describe orbital inflammatory granulation in a pregnant patient as an orbital complication of sinusitis.