The move by the California-based tech giant provides will allow even greater access to the growing economies where its iPhone and iPad have proved massively popular.
Customers will now be able to choose from more than 28 million songs, including from Asian stars, as well as a huge collection of movies from studios such as 20th Century Fox, Paramount, Universal, Disney and Warner Brothers.
Previously customers could only download applications via the company's App Store.
The iTunes Store is now open to consumers with credit cards issued in Brunei, Cambodia, Hong Kong, Laos, Macau, Malaysia, Philippines, Singapore, Taiwan, Thailand, Sri Lanka and Vietnam.
It was already available in Japan, Australia and New Zealand.
However, the expansion did not include China and India, which have a combined population of 2.5 billion and a growing middle class eager to spend their new-found wealth.
"We're always working to bring the iTunes Store to more customers around the world, as conditions permit," Apple said in a written reply to AFP when asked why China and India were not yet included.
More than 16 billion songs have been sold through the iTunes Store since it was launched in 2003, according to Apple figures.
In March, the firm announced that more than 25 billion apps had been downloaded from the App Store by the users of more than 315 million iPhone, iPad and iPod touch devices.