The assassination attempt of Donald Trump brought his former physician Ronny Jackson rushing to his side to render aid ... but, it appears Jackson's medical licenses are expired.

TMZ has checked, and it turns out Jackson's Virginia medical license expired back in 2020 ... so, technically it seems he's not allowed to treat patients.

The Dallas Morning News reports his Florida license expired when he retired from the Navy in 2019, but they say he's still American Board of Emergency Medicine certified to provide emergency medical services ... a certification that lasts until 2025.

That said ... while Trump was rushed to a medical facility in Pennsylvania, Congressman Jackson didn't meet up with him until he landed in Bedminster, New Jersey. It's unclear if he was legally allowed to provide care at that point.

Jackson provided a full memo describing his own evaluation of Trump Saturday morning ... admitting he'd been treating the former president and would continue to do so until he flies back to Washington, D.C. Monday.

BTW ... Jackson was reportedly detained during an incident last year when he tried to render aid to a 15-year-old who had a seizure at a Texas rodeo.