Non-governmental organisation Transparency International started the corruption perception index, which was at first measured on a scale of 0-10. But since 2012, it has been measured on a scale of 0-100, where 100 stands for the cleanest and 0 stands for the most corrupt country.

South Sudan is the most corrupt country in the world as of December 2024. The country has a "kleptocratic system" where corrupt practices range from bribery, oil revenue embezzlement, and black market benefits for the elites.

Somalia ranks 179 out of 180 countries in the 2024 corruption perception index. It moved from a score of 11 towards 9. The country has a system of patronage, bribery, and misuse of public funds. Researchers have shown that the political elite form a bureaucratic bourgeoisie, which uses state institutions and political position to accumulate wealth.

Venezuela scored 10 out of 100 in the 2024 Corruption Perceptions Index reported by Transparency International. This is the worst performance of the country, reaching a score of 28 in 2001 with an average of 20.28 points from 1995 to 2024.

Syria ranks 177 out of 180 nations in the 2024 corruption perception index. It reached an all-time high of 34.00 in 2004. Nepotism, and patronage had institutionalised corruption during the Ba'athist regime, and the abuse continued and benefited the Assad regime.

Yemen scored 13 points out of 100 on the 2024 Corruption Perceptions Index reported by Transparency International. Corruption Index in Yemen averaged 19.45 Points from 2003 until 2024, reaching an all-time high of 27.00 Points in 2005 and a record low of 13.00 Points in 2024

The political stalemate and the rival governments have plagued Libya. The two factions' de facto government Government of National Unity (GNU) in Tripoli, and a parallel government in the east constantly fighting about the oil revenue from the National Oil Corporation (NOC) and the Central Bank of Libya (CBL). The corruption has become extreme and systemic.

Eritrea scored 13 points out of 100 on the 2024 Corruption Perceptions Index reported by Transparency International. Corruption Index in Eritrea averaged 22.71 Points from 2004 until 2024, reaching an all-time high of 29.00 Points in 2006 and a record low of 13.00 Points in 2024.

Equatorial Guinea scored 13 out of 100, in October 2024. Vice President, Teodoro Nguema Obiang Mangue, had been at the centre of the corruption scandal, systematically drawing national oil revenue to family use.

Nicaragua ranked 172nd among the 180 countries in the Index. Its former President Alemán was formally charged in December 2002 and was sentenced to 20 years in prison. However, he later struck a deal with then-President Mr Daniel Ortega. Alemán is ranked as one of the world's 10 most corrupt leaders ever by Transparency International.

Sudan completes the top 10 most corrupt nations in the world. Corruption in Sudan is systematic and pervasive. 0.9 for political stability, 6.2 for rule of law, 7.2 for regulatory quality, 6.7 for government effectiveness, and 4.3 for control of corruption