The controversial idea was suggested by the US President as he met survivors of the Marjory Stoneman Douglas High School attack, as well as the parent of a child who was killed.
Students at the targeted school have been campaigning for stricter gun legislation in the aftermath of the tragedy.
Outlining his plan to prevent future high school gun massacres, Trump said: “If you had a teacher … who was adept at firearms, it could very well end the attack very quickly.”
Students wept as they told the President their stories from the day of the shooting in the State Dining Room at the White House and pleaded for a change in the law.
Despite putting forward the suggestion of arming teachers in the classroom, Trump vowed to improve background checks on gun buyers.
He also said his administration would do more to help those living with mental health.
He added: “We’re going to be very strong on background checks, we’re doing very strong background checks, very strong emphasis on the mental health.
“It’s not going to be talk like it has been in the past.”
A task force supported by the powerful pro-guns lobby group, the National Rifle Association, has previously recommended more armed guards and teachers in schools.
Since Trump’s meeting Sheriff Scott Israel, who is in charge of Broward County in Florida where the Marjory Stoneman Douglas High School is based, has announced he will deploy rifles to trained resource officers at all schools in his region.
He said: “Schools as soft targets need to be fortified.”
He added: “It will be done safely.
“We need to be able to defeat any threat that comes onto campus.”
A total of 17 people were killed when 19-year-old Nikolas Cruz used an AR-15 assault rifle to open fire at the Florida high school on February 14.
The incident was the second-deadliest shooting at a US public school in history.
Speaking to the President Sam Zeif, 18, sobbed as he recalled his account of the day.
He said: “I don’t understand why I can still go in a store and buy a weapon of war, an AR.
“Let’s never let this happen again please, please.”
Meanwhile, Andrew Pollack, whose daughter Meadow Pollack, 18, was killed in the attack, shouted: “It should have been one school shooting and we should have fixed it.
“And I’m pissed – because my daughter – I’m not going to see again.”
The right to own a gun is enshrined in the US constitution under the Second Amendment.
The gun lobby has previously pushed back on efforts for gun control arguing that such reform infringes their civil right to bear arms.