Chief executive Richard Burnett said drivers faced "a desperate situation", with gangs of migrants, some of them armed, trying to board vehicles.
"Things are beginning to boil over," he added.
The Home Office said security had been stepped up in recent days.
In the early hours of Saturday, about 150 migrants tried to storm the Channel Tunnel terminal at Calais, entering restricted areas and causing disruption to services.
The situation at the port has escalated in recent weeks with about 3,000 people from countries including Eritrea, Syria and Afghanistan setting up camp nearby.
Wildcats strikes by French ferry workers have compounded the problem, causing long queues of lorries to build up at the terminal and leaving them vulnerable to attempts by migrants to stow away on board.
Mr Burnett reiterated the RHA's call for action from the French military to boost security and help struggling drivers.
"Put yourself in their situation - you are on your own trying to get through and you've got 20 migrants around your truck trying to get on, and you're on your own trying to get them off," he said.
"They are intimidating, some of them have metal bars, knives and, in one incident, a gun was pointed at a trucker."
He added: "Somebody is going to get killed."
Eurotunnel increased security on Saturday night following the earlier disruption, and a full service was able to run.
Operation Stack - in which lorries are forced to queue on the M20 in Kent while awaiting an opportunity to cross the Channel - has also been lifted.
On Saturday, Keith Vaz, chairman of the Home Affairs Select Committee, visited Calais and held a meeting with deputy mayor, Philippe Mignonet to discuss the crisis.
Mr Mignonet wants the UK to introduce ID cards and employment controls in an effort to deter migrants.
Mr Vaz said the UK and France must work together to find a solution, and called for much more to be done to stop people arriving "in the EU itself" via countries like Greece and Turkey.
Home Secretary Theresa May and her French counterpart Bernard Cazeneuve agreed this week to increase the joint intervention fund to improve security in at the ferry port and Channel Tunnel terminal.
A Home Office spokesman said: "Law and order in and around Calais is the responsibility of the French authorities, but the UK continues to work with its French counterparts to strengthen the security of the border to stop illegal immigrants entering the UK."
Somebody is going to get killed unless action is taken to protect lorry drivers caught up in the growing migrant crisis at Calais, the Road Haulage Association is warning.