Speaking in an interview with the A-Haber television channel, Erdogan said Ankara "is determined to bring this case before international justice," and calls on the United States to weigh in this case.
"We are determined to take this matter to the international court.
Our justice ministry, foreign ministry and intelligence agency are working on this matter."
In October, a few weeks after the killing, four prominent rights groups - Human Rights Watch, Amnesty International, the Committee to Protect Journalists and Reporters Without Borders - urged the Turkish government to ask the UN to probe into the disappearance of the ill-fated journo.
Erdogan further criticized the US for “casting aside” the case of Khashoggi due to its bilateral ties with Saudi Arabia, urging Washington to “put its presence and weight” behind the issue.
"The CIA has not yet put its full weight behind this issue. We have a lot of expectations from the US on this matter. The US needs to put its presence, its weight here,” he said.
Erdogan also noted that Turkey has not yet revealed all the information it has discovered about the killing of Khashoggi.
"We haven't given all the elements we have at our disposal," he noted.
After weeks of denial, Saudi Arabia admitted that Khashoggi had been killed on October 2 after entering the consulate to obtain the paperwork necessary for his upcoming marriage to Turkish woman Hatice Cengiz.
Turkey has said the journalist was killed by a team of 15 Saudis who strangled him, and Ankara has repeatedly asked Riyadh to identify the local who allegedly helped them dispose of the body, which has not been found.
Riyadh has arrested a number of senior Saudi officials allegedly involved in the murder. Khashoggi, a Washington Post contributor, was a fierce critic of Saudi Crown Prince Mohammed bin Salman, who denies any involvement in the murder.
Erdogan has already said that the order to slay Khashoggi had been issued from “the highest levels” of the Saudi government, suggesting that the crown prince had ordered such a gruesome murder.
However, the Saudi regime has sought to distance the heir to the Saudi throne from the assassination despite emerging evidence alleging otherwise.
A report by the US Central Intelligence Agency (CIA) said it had concluded that bin Salman had been behind the gruesome crime.
Saudi Arabia has been facing international condemnation over the brutal crime.