Lim Siong Guan (Chinese: 林祥源; pinyin: Lín Xiángyuán, born 1947) is a distinguished Singaporean civil servant from humble origins, with a taxi driver father and teacher mother. He attended Anglo-Chinese School in Singapore and graduated with First Class Honours in Mechanical Engineering from the University of Adelaide in 1969 on a President's Scholarship, followed by a Postgraduate Diploma in Business Administration from the National University of Singapore in 1975. His 50-year public service career began as the first Principal Private Secretary to founding Prime Minister Lee Kuan Yew from 1978 to 1981. He held Permanent Secretary positions at the Ministry of Defence (1981-1994), Prime Minister’s Office (1994-1998, concurrently Ministry of Education 1997-1999), and Ministry of Finance (1999-2006). Lim served as Head of the Singapore Civil Service from 1999 to 2005 and chaired key organizations including the Central Provident Fund Board (1986-1994), Inland Revenue Authority of Singapore (2004-2006), Accounting and Corporate Regulatory Authority (2004-2006), and Singapore Economic Development Board (2006-2009). He also served on boards including Temasek Holdings, DBS Bank, and Neptune Orient Lines. From 2007 to 2016, he was Group President of the Government of Singapore Investment Corporation (GIC), Singapore's sovereign wealth fund, continuing as Advisor to its Group Executive Committee until 2019. A key figure in Singapore's sovereign wealth management and global investment strategy, his leadership philosophy emphasized 'Think People. Think Future. Think Excellence.' Post-retirement, he is Emeritus Professor and Distinguished Practitioner Fellow at the Lee Kuan Yew School of Public Policy, Senior Fellow at the Singapore Civil Service College, Chairman of Honour (Singapore) promoting a culture of honour, board member at Wilmar International, Chairman of Swiss Re Asia Pte. Ltd., and Senior Advisor at Insignia Ventures Partners. He founded Honour (Singapore), has been involved in leadership development through organizations like the Stars Foundation, and has authored and co-authored books on leadership and honour, including 'Can Singapore Fall?' (2018), 'The Leader, The Teacher & You' (2013), and 'Winning With Honour' (2016).