The 4-0 vote by the International Trade Commission sets up a two-month review period in which the panel must recommend a remedy to President Donald Trump, with a final decision on tariffs expected in January.
White House spokeswoman Natalie Strom said Trump "will examine the facts and make a determination that reflects the best interests of the United States. The US solar manufacturing sector contributes to our energy security and economic prosperity."
Cheap imports have led to a boom in the US solar industry, where rooftop and other installations have surged tenfold since 2011.
The main trade group for the solar industry and many governors oppose tariffs, saying they could cause a sharp price hike that would lead to a drop in solar installations by more than 50 per cent in two years.
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Abigail Ross Hopper, president and CEO of the Solar Energy Industries Association, called the trade commission's vote disappointing for nearly 9,000 US solar companies and the 260,000 Americans they employ.
Suniva's US operations are based in Georgia, but the company's majority owner is in China. SolarWorld Americas is a subsidiary of German solar giant SolarWorld, which declared insolvency last month.
Suniva hailed the ruling.
"It will be in President Trump's hands to decide whether America will continue to have the capability to manufacture this energy source," the company said in a statement.
Trump has not cozied up to the solar industry, as he has for coal and other fossil fuels, but he is considered sympathetic to imposing tariffs on solar imports as part of his "America first" agenda.
Governors of four solar-friendly states, Nevada, Colorado, Massachusetts and North Carolina, oppose the tariff, warning it could jeopardise the industry.
They cited a study showing that a global tariff could cause solar installations to drop by more than 50 per cent in two years, a crushing blow as states push for renewable energy that does not contribute to climate change.