Oligopoly is a market form which is controlled by a small amount of competitors known as oligopolists (Economicsonline.co.uk, 2013). The companies that dominated oligopoly competition are usually maintain the position in the market because it is too costly or difficult to any potential rivals to enter the company which mean there are entry barriers. Apple Inc. is oligopoly in the smartphone’s operating systems’ firm. There are 3 mainly operating systems which is very competitive in the market are iOS, owned by Apple Inc., Android, which is owned by Google, Windows phone, owned by Microsoft. These 3 are the most competitive operating systems throughout the world, and they keep on adding new features to the operating systems to dominate the rivals.