Princess Toto is a three-act comic opera by W. S. Gilbert and his long-time collaborator Frederic Clay. Its pre-London tour opened on 24 June 1876 at the Theatre Royal, Nottingham, starring Kate Santley, W. S. Penley and J. H. Ryley. It transferred to the Royal Strand Theatre in London on 2 October 1876 for a run of only 48 performances. Brief New York and Boston runs followed in 1879–80 starring Leonora Braham and Ryley, and there were later tours in the US. Princess Toto was revived in 1881 at the Opera Comique in London for a run of 65 performances. There was also an 1886 revival in Australia.

Sir William Schwenck Gilbert was an English dramatist, librettist, poet and illustrator best known for his collaboration with composer Arthur Sullivan, which produced fourteen comic operas. The most famous of these include H.M.S. Pinafore, The Pirates of Penzance and one of the most frequently performed works in the history of musical theatre, The Mikado. The popularity of these works was supported for over a century by year-round performances of them, in Britain and abroad, by the repertory company that Gilbert, Sullivan and their producer Richard D'Oyly Carte founded, the D'Oyly Carte Opera Company. These Savoy operas are still frequently performed in the English-speaking world and beyond.