President Donald Trump has issued an emergency order to immediately ground all Boeing 737 Max aircraft following the crash of an Ethiopian Airlines jet.
The Federal Aviation Administration had previously held out while many countries banned the aircraft from flying over their airspace.
President Trump said the planes will not fly until Boeing "comes up with a solution".
Boeing said it will suspend the entire 371-strong fleet of 737 Max planes.
The US is the last country to suspend the aircraft following the disaster.
The crash on Sunday in Addis Ababa killed 157 people.
It was the second fatal Max 8 disaster in five month after one crashed over Indonesia in October, killing 189 people.
Boeing said on Wednesday that it had decided to temporarily ground the planes "out of an abundance of caution and in order to reassure the flying public of the aircraft's safety".
American Airlines said that the FAA had had informed the company that "based on new information, they are grounding the United States Boeing 737 MAX fleet out of an abundance of caution".
Earlier on Wednesday, Canada grounded the planes after its transport minister Marc Garneau said he had received new evidence about the crash.
He said that satellite data showed possible similarities between flight patterns of Boeing 737 Max planes operating in Canada and the Ethiopian Airlines plane that crashed.
He said: "As a result of new data that we received this morning, and had the chance to analyze, and on the advice of my experts and as a precautionary measure, I issued a safety notice."
Dennis Muilenburg, president, chief executive and chairman of Boeing, said: "We are doing everything we can to understand the cause of the accidents in partnership with the investigators, deploy safety enhancements and help ensure this does not happen again."
American Airlines, which has 24 aircraft affected by the suspension, said: "Our teams will be working to rebook customers as quickly as possible, and we apologize for any inconvenience."