The Commerce Department said on Wednesday the current account gap, which measures the flow of goods, services and investments into and out of the country, rose 1.9 percent to $100.3 billion from a revised $98.4 billion deficit in the second quarter.
Economists polled by Reuters had forecast the deficit narrowing to $97.5 billion from a previously reported $98.5 billion shortfall in the April-June quarter.
The current account deficit represented 2.3 percent of gross domestic product, unchanged from the second quarter.
The deficit had declined in recent quarters as the U.S. ramped up domestic energy production, which has reduced its petroleum import bill.
With crude oil prices at 5-1/2 year lows, the current account gap is expected to narrow in the coming quarters.
Goods and services exports increased 0.9 percent to $592.0 billion in the third quarter, while imports slipped 0.2 percent to $716.3 billion.
The surplus on primary income rose to $59.0 billion in the third quarter from $54.8 billion in the prior quarter.
The deficit on secondary income increased to $34.9 billion from $22.0 billion in the second quarter. Secondary income receipts fell to $27.8 billion from $40.1 billion. Secondary income receipts had been boosted by fines and penalties paid to the U.S. government by foreign entities.