The bill now heads to the House, which is solidly supportive. Republican Gov. Ron DeSantis has indicated he will sign it into law if it passes.
The proposal has prompted fierce partisan debate. Students, including some from Parkland, traveled to Tallahassee to urge state lawmakers to defeat the bill.
Teachers would not automatically be authorized to carry guns. School boards would have to authorize it. South Florida school officials have resisted arming school employees.
In districts that choose to participate, educators who want to be armed would be required to pass a psychological evaluation and complete at least 144 hours of training.
Democrats tried repeatedly, but failed, to remove the language that would allow teachers to carry guns.