Venezuelan Embassy charge d'affairs Ariel Vargas said he received a letter from the Honduran Foreign Ministry ordering his diplomats to leave in 72 hours.
Venezuela's President Hugo Chavez has been the most vociferous critic of what he calls the "gorilla" government that overthrew his ally, Manuel Zelaya, on June 28.
The interim government accused Venezuela of meddling in Honduran affairs and of threatening to use its armed forces against Honduras, according to a copy of the letter obtained by The Associated Press.
Chavez has demanded Washington do more, including withdrawing U.S. troops from its Honduran base, to force Zelaya's return to power.
The European Union, meanwhile, warned Tuesday that if talks to end the crisis fail, it may impose further sanctions against the government of Roberto Micheletti, whom congress swore in as president after the coup. The EU announced on Monday that it had already frozen some euro65 million ($92 million) in aid to Honduras.
Swedish Foreign Minister Carl Bildt - whose country holds the rotating EU presidency - said the bloc is "considering different ways" to support mediation efforts by Costa Rican President Oscar Arias. He did not elaborate.
The 27-nation EU has condemned the coup and has called for Zelaya to immediately be returned to power.
No government has recognized the Micheletti administration, and the United Nations and Organization of American States have called for the return of Zelaya.
U.S. Secretary of State Hillary Clinton has told Micheletti there would be serious consequences if his government keeps ignoring international calls for Zelaya's return - the key point that led to a stalemate in U.S.-supported negotiations over the weekend.
Micheletti has vowed not to back down, and he sent a team to Washington this week to ward off economic sanctions by painting the coup backers as a bulwark against "dictatorship" and "communism."
Zelaya angered many people in Honduras by ignoring Congress' and the courts' objections to his effort to hold a referendum on changing the constitution, which many saw as an attempt to impose a Chavez-style socialist government.
Appealing to free trade supporters, Micheletti's team of lobbyists hope to nudge the Obama administration away from its threat to impose sanctions on the impoverished country, where export-assembly factories are dominated by U.S. firms and investors.
Business executives say U.S. Ambassador Hugo Llorens has called them into meetings to warn that Honduras could face tough sanctions if leaders continue to refuse Arias' compromise proposal for Zelaya to return as head of a coalition government. The U.S. Embassy said it would not comment on the meetings.
Micheletti has said he will stay in power until a scheduled Nov. 29 presidential vote, which the United States has suggested it may not recognize if it is held under a de facto government.