We describe the presentation and treatment of an HIV-positive patient with an oral ranula, and review the literature. Ranulas are mucoceles or retention cysts formed by the extravasation of mucus from the sublingual gland, presumably due to continued production of saliva in the presence of ductal obstruction. Oral ranulas in children are rare and the overall prevalence of mucoceles has been reported as 0.08% in children aged 0–12 years. However, there has been a documented increased occurrence in HIV-positive patients. This has been attributed to a blockage of the salivary gland by inflammation and peri-ductal fibrosis following HIV-associated salivary gland disease. Oral lesions may indicate infection with HIV and can also predict progression of HIV to AIDS. The most common oral manifestation is oral candidiasis occurring in 67% of children with HIV. Following this salivary gland disease, periodontal and gingival disease and herpes simplex are the next most common. The exact prevalence of ranulas in an HIV population is not known but the occurrence of a paediatric patient with HIV having at least one oral lesion has been documented as high as 63% and salivary gland disease at 50%. The true extent of the relationship between HIV and ranula is as yet unknown. This represents the only reported case of oral ranula in an HIV-positive patient in the UK.