The United States, which had already paused assistance after the military takeover, said it had formally determined that a coup took place, which under US law requires an end to non-humanitarian aid.
"We will resume our assistance alongside concrete actions by the transitional government toward establishing democratic rule," State Department spokesman Matthew Miller said in a statement.
"The United States stands with the Gabonese people in their aspirations for democracy, prosperity and stability."
Unlike in Niger, another African country where the United States recently severed aid over a coup, US assistance has been minimal to Gabon, which is wealthy from oil and was run by the Bongo family for more than half a century.
Gabonese military leaders overthrew Ali Bongo Ondimba just as he was proclaimed the winner of an election widely criticized for irregularities.
The military installed as prime minister Raymond Ndong Sima, who had been an opposition leader.
Ndong Sima has pleaded with Western powers not to paint all military takeovers with the same brush, saying that the intervention prevented unrest and addressed concerns on corruption.
The deposed president's Franco-Gabonese wife, Sylvia Bongo Ondimba Valentin, was jailed this month for alleged embezzlement of public funds.