Elevation of intraocular pressure (IOP) and glaucoma can be caused by intraocular tumors, which can be primary or metastatic. The risk of glaucoma is determined by the tumor type and location. Both closed- and open-angle glaucoma can occur. Glaucoma is estimated to occur in approximately 3–7.5% of patients with intraocular tumors. Any patient with unilateral elevation of IOP should raise suspicion for glaucoma secondary to intraocular malignancy. Even after successful tumor ablation, glaucoma and its deleterious effects persist. Glaucoma secondary to intra-ocular tumors often poses difficult management issues both in the short and long term. It is important to recognize glaucoma as a sight-threatening complication of intra-ocular tumors in both adults and children.