Macharia Kamau (born 3 March 1958) is Kenya's Principal Secretary to the Ministry of Foreign Affairs.

In 1983, he obtained a Master of Education in Administration and Social Policy from Harvard University, in Cambridge, Massachusetts, United States.

He has also served on UN special assignments, and was President of the United Nations Children’s Fund (UNICEF) Executive Board (2014); President of UN Forests Forum (2011-2012), Co-Chair of the Ad hoc Working Group on Forest Financing (2010-2011), Vice President of the 67th Session of the UN General Assembly, Co-Chair of the General Assembly Working Group on the Sustainable Development Goals (SDGs) (2012-2014) and as co-facilitator of the post 2015 Development Agenda (2014-2015).

[4][5] In October 2016, President of the United Nations General Assembly Peter Thomson created a Sustainable Development Goals implementation team "in order to motivate actors at global, regional, national, and community levels" and appointed Kamau as the Special Envoy on Implementation and Climate Change.

[8] Kamau is the co-author of Transforming Multilateral Diplomacy: The Inside Story of the Sustainable Development Goals[9] published in February 2018.