Hilda "H.D." Doolittle (September 10, 1886 – September 27, 1961) was an American poet, novelist, and memoirist known for her association with the early 20th century avant-garde Imagist group of poets such as Ezra Pound and Richard Aldington. She published under the pen name of H.D..

HD may refer to:

• Higher diploma, an academic award
• National History Day, an American history competition, somewhat similar to Science Fair