The sanctioned individuals are Iranian nationals Rahim Ahmadi and Morteza Farasatpour and Chinese citizen Ruan Runling, according to OFAC.
The designated entities include Matin Sanat Nik Andishan, Shanghai Gang Quan Trade, Shanghai North Begins International and Shanghai North Transway International Trading.
The two Iranian individuals are senior defense officials, one of whom facilitated a sale of explosives to Syria, according to the Treasury.
"These sanctions target Iranian officials as well as a China-based network that are providing support to Syria and supplying items to further Iran’s ballistic weapons program. The United States will remain vigilant when it comes to Iran," Treasury Secretary Steven Mnuchin said in a release.
In February, the United States imposed sanctions against Iran after Tehran carried out a medium-range ballistic missile test in late January.