The retailer is opening the doors to a 1,300 square metre shop in the city's central business district.
Topshop boss Philip Green said he wants to use the store as a "stepping stone" to mainland China. He is looking for possible locations in Beijing and Shanghai to open "flagship" stores.
Other foreign retailers that have launched in the Asian finance centre recently include US brands Abercrombie & Fitch, Tommy Bahama and Forever 21.
Hong Kong is a popular shopping destination for mainland Chinese because of low taxes and a reputation for authentic goods.
Foreign brands have been lining up to open up showcase boutiques in Hong Kong as they try to get a share of the spending by the increasingly affluent consumers visiting from mainland China, the world's second biggest economy. The demand has helped drive up shop rents in Hong Kong, a former British colony that is now a special administrative region of China.
He said he was starting his search for mainland locations this week, with Chinese estate agents visiting him while he was in Hong Kong.
"I'd like to have a flagship in Beijing and a flagship in Shanghai," Mr Green said a day before the store opening.
"If we can find 2,000 to 3,000 square metres - we'd like to have a Topman as well - if we can find two locations, off we go."