UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

February 23, 2016

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:    x  Form 20-F     ¨  Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ¨

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934:    ¨  Yes    x  No

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): n/a

NEWS RELEASE

BHP BILLITON ANNOUNCES SIMPLIFIED OPERATING MODEL TO ACCELERATE PRODUCTIVITY AND VALUE CREATION

BHP Billiton today announced a new operating model that will create a more agile Company ready to respond to the challenges and opportunities presented by a rapidly changing global marketplace.

Under the changes announced today, BHP Billiton will become a much simpler organisation focused on geographic operating regions and supported by globalized functional services drawing upon world-class expertise and scale.

Andrew Mackenzie, BHP Billiton CEO, said: “These changes are a continuation of our simplification journey. They are made possible by the recent demerger of South32 and well-timed asset divestments, and reflect our continued commitment to improve productivity.

“At the core of the new model will be assets dedicated to safety, volume and cost enabled by functions integrated globally and largely co-located with the assets.

“Both assets and functions will have fewer layers and hence fewer people required to lead and run the organisation. This closer connection between management and operations will promote greater efficiency, rapid sharing of best practice and adoption of new technology to improve safety, productivity and learning - as well as management of risk.

“Our focused portfolio of tier one assets will now be managed through a vastly simplified operating model, positioning BHP Billiton to create new opportunities for value and growth into the future.”

BHP Billiton’s minerals production operations will be organised into two regional units - Minerals Australia and Minerals Americas. The Company’s oil and gas exploration and production operations will continue to be housed within a global Petroleum unit, reflecting the operating environment in that sector.

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Under the Business changes announced today:

The changes, which are effective 1 March 2016, mean that one less President role will be required in Australia, and as a result Jimmy Wilson, currently President Iron Ore, will leave the Company. As the role of President Petroleum will change to become more closely focused on operations and will no longer include direct oversight of functional and business administration, it has been agreed that Tim Cutt, currently President Petroleum, will also leave the Company.

Mr Mackenzie said: “I sincerely thank Jimmy and Tim for their exceptional leadership and service to BHP Billiton over many years.

“Jimmy Wilson has transformed Western Australia Iron Ore into one of BHP Billiton’s most important Businesses and has led the way in introducing a simpler, more effective organisational model which continues to drive significant value for our shareholders.

“As President Petroleum, Tim Cutt has led the US onshore industry in achieving productivity gains that were unheard of just a few years ago. His leadership has seen BHP Billiton’s Petroleum Business gain global recognition for its operational excellence.

“On behalf of all at BHP Billiton, I wish Jimmy and Tim every success and thank them for all they have done for the Company.

“I congratulate Steve Pastor on his appointment as President Operations, Petroleum and welcome him to the Company’s executive leadership team.”

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In addition to these changes, Dean Dalla Valle has been assigned to lead the Company’s response to the Samarco dam failure. He will be based in Brazil in recognition of this significant event and the Company’s commitment to support Samarco in the response and recovery effort. Mr Dalla Valle will retain responsibility for the Jansen Potash project in Canada and will continue to report to the CEO.

Mr Mackenzie also outlined the changes to BHP Billiton’s functional model to improve the efficiency and capability of service delivery to the Company. These changes include the transition of key functional services to global reporting lines. This will eliminate duplication of effort and create deep pools of expertise in the provision of services to the Company’s operated Assets. The key changes are:

Mr Mackenzie and all his direct reports will constitute BHP Billiton’s Executive Leadership Team (ELT), which will have responsibility for the day-to-day management of the Company. The members of the ELT are:

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Further information on BHP Billiton can be found at: bhpbilliton.com

Members of the BHP Billiton Group which is

headquartered in Australia

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.