The Sandwich tern ("Thalasseus sandvicensis") is a tern in the family Laridae. It is very closely related to the lesser crested tern ("T. bengalensis"), Chinese crested tern ("T. bernsteini"), Cabot's tern ("T. acuflavidus"), and elegant tern ("T. elegans") and has been known to interbreed with the lesser crested.
Interbreeding has been reported between terns in the family Laridae and lesser crested terns.