The Perthshire venue, which hosted golf's flagship Ryder Cup event in October last year, is expected to attract offers of around £200m. Drinks giant Diageo has owned Gleneagles since 1984, and has attempted to sell the resort before.
According to The Scotsman, property firm Jones Lang LaSalle has now been brought in by Diageo to look for potential buyers.
Last week, a spokesman for Diageo said: "Gleneagles is one of the UK’s finest luxury hotels and one of the world’s most fantastic golf resorts.
"We are sure there are many people who would love to own Gleneagles and have received numerous expressions of interest over the years, and particularly since the Ryder Cup.
"As you would expect, we have a duty to consider such interest carefully."
Gleneagles recently announced it was investing a further £1.1m in refurbishments, which followed the news it was opening a 2,500sqm conference venue in the spring.