The researchers found plant life in areas where vegetation was not previously known to grow.
A team used satellite data from 1993 to 2018 to measure the extent of plant cover between the tree-line and the snow-line.
The study focused on the subnival region - the area between the tree-line (the edge of the habitat at which trees are capable of growing) and the snow line (the boundary between snow-covered land and snow-free land).
Subnival plants are mainly small grasses and shrubs.
"The strongest trend in increased vegetation cover was between 5,000 metres and 5,500 metres altitude," said Dr Karen Anderson, from Exeter University, lead author of the report.
"At higher elevations, the expansion was strong on flatter areas while at lower levels that has been observed on steeper slopes."
Using Nasa's Landsat satellite images, the researchers divided the heights into four "brackets" between 4,150m and 6,000m.It covered different locations in the Hindu Kush Himalayas, ranging from Myanmar in the east to Afghanistan in the west.
It covered different locations in the Hindu Kush Himalayas, ranging from Myanmar in the east to Afghanistan in the west.
In the Everest region, the study found a significant increase in vegetation in all height brackets.
Other researchers and scientists working on glaciers and water systems in the Himalayas have confirmed the expansion of vegetation.
"It (the research) matches the expectations of what would happen in a warmer and wetter climate," said Prof Walter Immerzeel, with the faculty of geosciences at Utrecht University in the Netherlands, who was not involved in the study.
"This is a very sensitive altitudinal belt where the snowline is. A withdrawal of the snowline to higher altitudes in this zone provides opportunity for vegetation to grow."
The research did not examine the causes of the change.
Other research has suggested Himalayan ecosystems are highly vulnerable to climate-induced vegetation shifts.