Sir Donald MacAlister, 1st Baronet of Tarbet KCB FRSE (17 May 1854 – 15 January 1934) was a Scottish physician who was Principal and Vice-Chancellor and, later, Chancellor of the University of Glasgow.

He rose in life from humble beginnings via school at the Liverpool Institute for Boys (founded 1825, closed 1985) to achieve the highest score in the final mathematics examinations at the University of Cambridge in 1877.

After a spell teaching mathematics at Harrow School, MacAlister returned to his original intention of studying medicine, first at Cambridge, later in 1879 at St. Bartholomew's Hospital, and for a short time at Leipzig.

In addition to his native Gaelic and English, he was said to have spoken well German, Norse, French, Italian, Dutch, Spanish, Portuguese, Czech, Basque, Turkish, Greek, Arabic, Swedish, Russian, Serbian, Afrikaans and Romany: nineteen languages total.

MacAlister also assisted Inagaki Manjiro with a petition to the Council of the Senate to allow Japanese students to obtain exemption from the study of Latin and Greek for entrance examinations.

MacAlister's work was widely recognised; he received honorary doctorates from thirteen universities and was appointed KCB in 1908 and created a baronet, of Tarbert, Cantire, in the County of Argyll, in 1924.