Commander Mark Raymond Tandy, CSC & Bar is an officer of the Royal Australian Navy (RAN).

On exchange with the Royal Navy in 2005, he spent four months at HMS Collingwood as a lead instructor at the Command and Training Group.

He was appointed to the rank of lieutenant commander and served as executive officer of Naval Headquarters, South Queensland.

[4] In the 2022 Queen's Birthday Honours, he was awarded a Bar to his Conspicuous Service Cross for his "outstanding devotion to duty" in leading the Indigenous Development Program.

[5] Tandy holds a Master in Maritime Studies degree from the Australian Command and Staff College at Weston Creek (2007).