The term harp ukulele is used to describe two different variants of the ukulele:
The harp ukulele appeared in the 1910s, when the harp guitar was experiencing some popularity, and the ukulele had just begun to experience nationwide popularity in the United States due to its use at the Panama–Pacific International Exposition of 1915.
After the popularity of both the harp guitar and ukulele faded, the harp ukulele lost what little market share it had. However, in the late 20th century various luthiers returned to experimenting with the harp ukulele design, both the string-less extended-bout type, as well as the added-strings true harp type.