This is a list of heads of state, heads of governments, and other rulers in the year 2003.
- Afghanistan
- Bahrain
- Bangladesh
- Bhutan
- Brunei
- Cambodia
- China (People's Republic of China)
- East Timor
- India
- Indonesia
- Iran
- Iraq (under an occupation led by the United States)
- following the 9 April fall of the capital, the occupied Ba'athist Iraq was superseded ensuing invasion on 21 April
- President – Saddam Hussein, President of Iraq (1979–2003)
- Administrator –
- Jay Garner, Civilian administrator of Iraq (2003)
- Paul Bremer, Civilian administrator of Iraq (2003–2004)
- Head of Government –
- Saddam Hussein, Prime Minister of Iraq (1994–2003)
- Mohammad Bahr al-Ulloum, President of the Governing Council of Iraq (2003)
- Ibrahim al-Jaafari, President of the Governing Council of Iraq (2003)
- Ahmed Chalabi, President of the Governing Council of Iraq (2003)
- Ayad Allawi, President of the Governing Council of Iraq (2003)
- Jalal Talabani, President of the Governing Council of Iraq (2003)
- Abdul Aziz al-Hakim, President of the Governing Council of Iraq (2003)
- Israel
- Japan
- Jordan
- Kazakhstan
- North Korea (Democratic People's Republic of Korea)
- South Korea (Republic of Korea)
- Kuwait
- Kyrgyzstan
- Laos
- Lebanon
- Malaysia
- Maldives
- Mongolia
- Myanmar
- Nepal
- Oman
- Pakistan
- Philippines
- Qatar
- Saudi Arabia
- Singapore
- Sri Lanka
- Syria
- Taiwan (Republic of China)
- Tajikistan
- Thailand
- Turkey
- Turkmenistan
- United Arab Emirates
- Uzbekistan
- Vietnam
- Yemen
- ^ Eritrea only became independent in 1993.
- ^ Bahrain only became independent in 1971.
- ^ Brunei only became independent in 1984.
- ^ Hun Sen was titled Second Prime Minister in 1993–98.
- ^ Kazakhstan only became independent in 1991.
- ^ The position of Chairman of the National Defence Commission was declared to be the highest office of state by the constitution that came into effect in 1998.
- ^ Kyrgyzstan only became independent in 1991.
- ^ Turkmenistan only became independent in 1991.
- ^ Uzbekistan only became independent in 1991.
- ^ Saleh was president of North Yemen until 1990.
- ^ Abkhazia only declared independence in 1992.
- ^ Transnistria only declared independence in 1991.
- ^ The seven-member Swiss Federal Council is head of state and government collectively. As a party to the Council, the president serves solely in a primus inter pares capacity for one year.
- ^ Tonga only became independent in 1970.
- Rulers—a list of rulers throughout time and places
- WorldStatesmen—an online encyclopedia of the leaders of nations and territories