His visit comes with Russian Deputy Foreign Minister Mikhail Bogdanov, President Vladimir Putin's special Middle East representative, also in Tehran.
IRNA said Bogdanov and Deputy Foreign Minister Hossein Amir-Abdollahian discussed "the situation in Syria and the region".
Iran and Russia are the two main allies of Syrian President Bashar al-Assad's regime. Tehran backs him both financially and militarily by sending military advisers.
Iranian media reported that a tripartite meeting between Zarif, Bogdanov and Muallem will also take place to discuss the conflict in Syria.
"The final solution in Yemen is political, in Syria the final solution is political. The agreement will create a new atmosphere. The climate will be easier," Rouhani said on state television.