Tunisian Prime Minister Youssef Chahed sacked Minister of Energy and four ministry officials on Friday over corruption allegations.
Government spokesperson Iyad al-Dahmani told a press conference that the move was due to allowing a Tunisian investor to explore and produce oil without a licence since 2009.
Gaddour was appointed in September 2017.
A committee of experts will be formed to restructure the ministry and review the sector's governance and an investigation will be held, a government statement said.
Chahed also decided to merge the Ministry of Energy, Mines and Renewable Energy with the Ministry of Industry.
Tunisia has been in the grip of an economic slowdown, resulting from the unrest that followed the 2010-11 revolt and ensuing attacks by militant insurgents.
Unemployment is around 15 percent and the country's budget deficit reached around 6 per cent last year, according to official figures.
The government has been carrying out austerity measures, which were met with protests in the North African country.
In June, the government increased fuel prices by 4 per cent in a bid to control the energy sector's deficit and the devaluation of the local currency.
Chahed, who vowed to fight corruption when he was appointed in 2016, launched a campaign since May 2017 against a number of businessmen on charges of money laundering and corruption, and several businessmen have been placed under house arrest.
