'LGBT-themed' originates from Modern English, formed by combining the acronym 'LGBT' (from the words 'lesbian', 'gay', 'bisexual', 'transgender') with the adjective-forming sense of 'theme' plus the suffix '-ed' to indicate 'having or relating to a theme'.

'Theme' ultimately comes from Greek 'thema' via Late Latin and Old French into Middle English as 'theme', and later took the participial/adjectival form 'themed'. The acronym 'LGBT' developed in late 20th-century English as an initialism for 'lesbian, gay, bisexual, transgender'; these elements were later compounded to form the modern compound adjective 'LGBT-themed'.

Initially, 'theme' (from Greek 'thema') meant 'that which is laid down' or 'a subject', and 'LGBT' began as a label for groups/identities; over time the compound 'LGBT-themed' came to mean 'having or dealing with topics related to LGBT people and issues'.