Rescue teams using helicopter air ambulances were working into the evening to stablise the injured people at the Nevis resort on Aonach Mor, just south of Fort William, and to assist in the rescue of the other stranded cable car passengers.
A spokesman for the Royal Air Force Kinloss mountain rescue said it is believed that at mid-afternoon two cable cars collided at a height of about 2,000 feet. The collision sent five occupants from one gondola falling about 65 feet onto the hillside.
Four adults and one child were thought to have been injured. All were reported to be conscious at the scene. There were no fatalities.
The five have injuries to the head, legs and arms; some of them have broken bones. They were to be transported to hospitals in nearby Fort William and to Inverness.
Fifty people were believed to be at the top of the mountain and may be forced to walk the approximately 2,100 feet to safety. Another 25 people were thought to be stranded in gondolas as the cable car system was shut down after the accident.
The cable car transports passengers from 300 feet at its lowest point up to 2,150 feet, on the north face of Aonach Mor. The ride takes about 15 minutes and each gondola can accommodate up to six people.
Aonach Mor, at 4,000 feet high, is the eighth-highest mountain in Britain. The cable car system on the mountain was originally built to take skiers to the slopes, however it has become a popular tourist attraction in warmer weather.
The weather on the mountain today was dry and bright. Winds were between 15-25mph.
Ben Nevis is Britain's tallest mountain, at 4,400 feet high.