Background: Generally presents in childhood, orbital lymphangioma is an uncommon unencapsulated vascular malformation of the lymphatic system. These benign cystic lesions represent 1%-4% of all orbital masses and may appear after an upper respiratory infection or minor trauma. Because of its nature, the management can be challenging and depends on the clinical presentation. We report an 8-year-old boy with orbital lymphangioma presented with acute proptosis. Then, we discuss different features of this disorder plus its management Case Presentation: An 8-year-old boy was presented with sudden left eye proptosis. He had normal visual acuity and color vision without ocular pain or diplopia. An infiltrative and diffused intraconal plus extraconal mass was detected in orbital computed tomography. Contrast-enhanced MRI revealed a multilobulated infiltrative heterogeneous lesion with fluid-fluid levels. The diagnosis was made on imaging, and he went under treatment with an oral corticosteroid. The symptoms were entirely resolved, and no recurrence occurred during the follow-up. There are several surgical and nonsurgical therapies for orbital lymphangioma. Still, the priority is conservative management, such as sclerotherapy (including OK-432, doxycycline, sodium tetradecyl sulfate, etc.), bleomycin, carbon dioxide laser, systemic corticosteroids, and so on. Conclusions: In most cases, the current imaging methods make a noninvasive diagnosis of orbital lymphangioma possible. Conservative management should be considered the first treatment.