Eustachius may refer to:
Saint Eustace (died 118), latinized as Eustachius, ancient Roman general and Christian martyr Eustáquio van Lieshout (1890–1943), also Eustachius, Dutch missionary in Brazil Eustachius, religious name of Joseph Kugler (1867–1946), German beatified religious
See also Sint Eustatius, Dutch island in the Caribbean Bartolomeo Eustachi (c. 1500–1510–1574), anatomist Eustasius of Bourges, 6th century Catholic saint, bishop, archbishop, deacon and archdeacon Eustathius (disambiguation) Eustochius, fifth bishop of Tours from 443 to 460