Mosaddeq, who is heading a high-ranking judiciary delegation, was received at the Dushanbe airport by Tajik officials and Iranian Ambassador to Tajikstan Mohammad Taqi Saberi.
As well as holding meetings with Tajik judiciary officials, he is planned to take part in the meeting of Supreme Court Chief Justices of the Shanghai Cooperation Organization (SCO) Member States.
The SCO is a transcontinental political, economic, and security alliance.
It was formed in 2001 by Russia, China, Kyrgyzstan, Kazakhstan, Tajikistan, and Uzbekistan at a summit held in Shanghai.
China, Kyrgyzstan, Pakistan, Russia, Tajikistan, India, Kazakhstan, and Uzbekistan are its current full members. Iran, Afghanistan, Belarus, and Mongolia are observer states.
The organization accounts for 40 percent of the world's population and 28 percent of the global gross domestic product (GDP).