Paranasal sinus mucocele is a benign disease resulting from obstruction of paranasal sinus ostia, leading to the paranasal sinuses’ mucus filling. This can lead to expansion and pressure on surrounding structures. The most commonly involved sinuses are the frontal and ethmoid. Paranasal sinus mucoceles are usually caused by obstruction of the sinus ostia, which leads to mucus filling of the sinuses. They can result from chronic inflammation and obstruction of sinus ostia; they can also result from previous endoscopic sinus surgery or facial trauma resulting in sinus flow tract obstruction. Paranasal sinus mucoceles are rare in children, but cystic fibrosis should be considered, especially in the paediatric population. Clinically, besides the usual symptoms of sinusitis, patients with mucoceles usually present specifically with headache or facial pain. However, patients can have an intracranial or orbital extension and may report visual changes or proptosis. Histologically, they are usually lined by pseudostratified columnar epithelium but, in some cases, may be associated with areas of squamous epithelium, inflammatory cell infiltration, bone resorption, and new bone formation. Surgery is the only curative treatment; endoscopic marsupialization has proven an effective therapeutic modality. Some patients with frontal mucocele will require combined access, especially when the lesion is located more laterally.