In their first face-to-face talks on the Gulf crisis, Erdogan and Qatari ruler Emir Sheikh Tamim bin Hamad Al-Thani discussed "joint efforts to fight terrorism and extremism... in all forms and sources of financing", and finding a "peaceful solution" to the crisis, state news agency QNA reported.
Erdogan's spokesman Ibrahim Kalin said the talks covered "developments in Syria and Iraq, the fight against terrorism... the importance of unity among Muslim countries and the importance of protecting countries' sovereign rights".
Turkey has sided with Qatar in the crisis, the worst to hit the region since the six-nation Gulf Cooperation Council was established in 1981.
On June 5, Saudi Arabia, the United Arab Emirates, Egypt and Bahrain suspended diplomatic and economic ties with Qatar over allegations that Doha had too close ties with Iran and supported Islamist extremist groups.
Qatar has denied the allegations.
On Sunday, Erdogan was in Kuwait, which is leading mediation efforts in the crisis, and also in Saudi Arabia, where King Salman hailed the Turkish leader's "efforts in the fight against terrorism and its financing".
Erdogan has voiced support for Kuwait's mediation efforts, a possible indication that Ankara sees the emirate as the key to resolving the crisis.
Qatar's emir said in an address to the nation on Friday that Doha was open to talks with the Saudi-led bloc on condition that his country's "sovereignty" was respected.
His call received a cold reception from the UAE's state minister for foreign affairs, Anwar Gargash, who wanted Qatar to review its policies.
"Dialogue is necessary, but it should be based on a revision" of Qatar's stance, he tweeted.
Qatar has emerged as Turkey's top ally in the Middle East in recent years, with Ankara and Doha closely coordinating over issues including the Syria conflict where the two are staunch foes of President Bashar al-Assad.
Turkey is also setting up a military base in Qatar, its only such outpost in the region. It has expedited the process since the crisis began and reportedly now has 150 troops in the emirate.