Oracle, like other software companies, has focused on expanding its remote data storage services in the face of changing corporate needs.
NetSuite, founded in 1998, is one of the first companies dedicated to providing services over the internet.
Oracle said the two firms' cloud applications were "complementary".
"We intend to invest heavily in both products - engineering and distribution," said Oracle chief executive Mark Hurd.
The deal is expected to be completed before the end of this year.
This is not Oracle's first move to expand its cloud services. The software company has bought Textura and Opower in the past few years.
NetSuite chief executive Zach Nelson said: "NetSuite will benefit from Oracle's global scale and reach to accelerate the availability of our cloud solutions in more industries and more countries.
"We are excited to join Oracle and accelerate our pace of innovation."
As the deal was announced, NetSuite also reported a 30% increase in its second-quarter revenues to $231m.
Software giant Oracle has announced it is buying NetSuite, a pioneer of the fast-growing world of cloud computing, in a deal worth $9.3bn (Â£7.1bn).