Birkholm is a small Danish island off the southern coast of Funen in Ærø Municipality. With an area of just , as of 1 January 2010 it has a population of 10. The flat, low-lying island is just over long and  above sea level at its highest point, though the protective dykes are high. It can be reached by post boat from Marstal on Ærø in 25 minutes.