Nearly 500 passengers were polled last autumn, with 95 per cent satisfied with punctuality and 80 per cent with value for money.
Transport Focus director David Sidebottom said: “It’s clear that Glasgow Subway users are pretty happy with their service and the value for money it gives.
“One area that the subway needs to address is the smoothness of the journey.”
The 122-year-old circle is undergoing a Â£288 million overhaul that will include Britain’s first underground trains with no staff on board.
Gordon Maclennan, chief executive of Strathclyde Partnership for Transport, which runs the Subway, said: “These are excellent results.
“We will need to continue to work hard to maintain, and even improve, our overall satisfaction score, but our dedication to staff training and good customer service is clearly demonstrated in these results.”