Oral submucous fibrosis is commonly seen in the adult population of the ethnic minorities in the UK, although its presentation in a child is rare. Whilst the condition is considered multifactorial and irreversible, we present a case of oral submucous fibrosis in a 12-year-old Bangladeshi boy whose cessation of habitual betel nut chewing and forcible mouth chewing exercises led to an improvement in his mouth opening, although his ability to protrude his tongue remained unaltered. The clinical features, pathogenesis and management of submucous fibrosis are described. The widespread use of betel quid among Asians in the UK is summarized and the importance of its recognition as a precancerous condition is emphasized.