Alexander John Ellis FRS (14 June 1814 – 28 October 1890) was an English mathematician, philologist and early phonetician who also influenced the field of musicology.

His other brother, William Henry Sharpe, served with the Lancashire Fusiliers after moving north with his family to Cumberland, due to military work.

Initially trained in mathematics and the classics, he became a well-known phonetician of his time and wrote the article on phonetics for the Encyclopaedia Britannica in 1887.

In part V of his series On Early English Pronunciation, he distinguished forty-two different dialects in England and the Scottish Lowlands.

He was acknowledged by George Bernard Shaw as the prototype of Professor Henry Higgins of Pygmalion (adapted as the musical My Fair Lady).