Mabel Leilani Smyth (September 1, 1892 – March 24, 1936) was a nursing administrator and the first Director of the Public Nursing Service for the Territory of Hawaii. She was of Hawaiian and Irish-English ancestry. Palama Settlement in Kalihi, where she had been the first head nurse of the program, eventually came under her authority at the Public Nursing Service. The Mabel Smyth Memorial Building in Honolulu, listed on the National Register of Historic Places, was erected in her honor.