Heinsius is a surname of Dutch and German origin. Notable people with that surname include:
Anthonie Heinsius (1641–1720), Dutch statesman Daniel Heinsius (1580–1655), Dutch scholar and poet Gottfried Heinsius (1709–1769), German mathematician, geographer and astronomer Johann Julius Heinsius (1740–1812), German oil painter and miniaturist Johann Samuel Heinsius (1686–1750), German bookseller and publisher Nicolaas Heinsius the Elder (1620–1681), Dutch scholar and poet, son of Daniel Heinsius Nicolaas Heinsius the Younger (1655–1718), Dutch physician and writer, son of Nicolaas the Elder
See also Heinsius (crater), on the Moon, named after Gottfried Heinsius