The U.S. International Trade Commission ruled that Apple did not violate a Google patent to make the popular iPhones.
Apple had initially been accused of infringing on six patents for iPhone-related technology covering everything from reducing signal noise to programming the device's touch screen so a user's head does not accidentally activate it while talking on the phone.
If Apple had been found guilty of violating the patent, its devices could have been banned from being imported into the United States.
Google can appeal the decision to the U.S. Court of Appeals for the Federal Circuit.
"We're disappointed with this outcome and are evaluating our options," the company said in a statement.
A spokeswoman for Apple declined comment.
The smartphone industry has seen dozens of lawsuits on several continents as Apple vies for market share with companies that make smartphones that use Google's Android software.
Google acquired the patents in the case - and the lawsuit - when it purchased Motorola Mobility for $12.5 billion in 2012, partly for its library of telecommunications patents.
Google's Android software, which the company lets handset makers use for free, has become the world's No. 1 smartphone operating system, ahead of the iOS software used on Apple iPhones.
The ITC, a U.S. trade panel that investigates patent infringement involving imported goods, is a popular venue for patent lawsuits because it can bar the importation of infringing products and because it issues decisions relatively quickly.
Motorola Mobility, which has since been acquired by Google, accused Apple in 2010 of infringing on six of its patents.
Two were terminated from the case, and the ITC said last August that Apple was innocent of infringing three others.
But the commission had also asked its internal judge, Thomas Pender, to reconsider its finding that Apple did not violate a fourth patent, which is for a sensor to monitor the location of a user's head to keep it from manoeuvring on the touch screen.
Pender found that patent obvious in December, and the full ITC came to the same conclusion this week.