Darwin Day is a recently instituted celebration intended to celebrate the anniversary of the birth of Charles Darwin on February 12, 1809. The day is also an opportunity to highlight Darwin's contribution to science and to promote science in general.

The celebration of Darwin's work and tributes to his life have been organized sporadically since his death on April 19, 1882, at age 73. Events took place at Down House, in Downe on the southern outskirts of London where Darwin and members of his family lived from 1842 until the death of Emma Darwin in 1896.

In 1909, 265 scientists and dignitaries from 167 countries met in Cambridge, England, to honor Darwin's contributions and to discuss vigorously the recent discoveries and related theories contesting for acceptance.