Beighton, aged 40, joins from leisure firm Luminar, where he is also finance director at present. Prior to joining Luminar, he was at Matalan, where he was head of finance.
Asos’s present finance director Jon Kamaluddin will become international director.
Asos chief executive Nick Robertson said: “These appointments are key to our plans to develop Asos internationally. Nick’s broad retail experience combined with his knowledge of operating within a FTSE 250 company will also be invaluable to us, and I am looking forward to working with him.”