"President Trump's agenda is to make sure that we have free and fair trade and I think, as you know, the United States is probably the most open trading market there is for both goods, services and investment," Mnuchin said.
But he said the United States expected to be treated as it treats others.
"The president believes in reciprocal trade deals and reciprocal free trade."
Mnuchin's comments came during a public conversation with Christine Lagarde, head of the International Monetary Fund, during the spring meetings of the IMF and World Bank, which are to wind down on Sunday.
With (Other OTC: WWTH - news) a nationalist economic agenda, the Trump administration has vowed to upend decades of prevailing trade policy by renegotiating or scrapping trade agreements, imposing tariffs and moving to bilateral trade agreements.
US pressure last month forced a Group of 20 finance ministers meeting in Germany to strike the routine commitment against protectionist policies from a closing statement.
The word "protectionism" also did not appear in the final statement of this week's meetings at the IMF.
"If our markets are open, there should be a reciprocal nature to other people's markets," Mnuchin said Saturday.
"What's not free and fair is if our market is open and other people either have high tariffs or have high import barriers."