The University of Oxford has kept top place in an international league table for a record-breaking ninth year in a row.
It's featured in the first position of the Times Higher Education (THE) world rankings.
There are more than 2,000 universities in the ranking list across 15 countries and the UK has 25 universities in the top 200 spots on the list, the same as last year.
However, experts have warned the reputation of the UK higher education sector is likely to "weaken" if the funding environment does not improve.
They say British institutions are being "battered by numerous prevailing winds", including stretched finances and restrictions on international students, which could make it hard to sustain its position in the future.
The annual THE list looks at five areas: teaching, research quality, research environment, international outlook, and industry.
Of the UK universities in the top 200, 13 institutions improved their ranking in the past 12 months, five stayed the same, and seven dropped by at least one place.
Oxford was named the best-performing university globally, ahead of Massachusetts Institute of Technology (MIT) in the United States, which took second place.
The University of Cambridge took fifth place in the list, for the second year in a row, while Imperial College London fell from eighth to ninth place.
Phil Baty, chief global affairs officer at THE, said: "While, overall, the picture of UK higher education in our rankings is positive, the sector is being battered by numerous prevailing winds.
"Chief amongst them is the extremely stretched finances it is facing and the restrictions on recruiting international students making it harder for them still, making it almost impossible to see how the sector can sustain its position in the coming years without significant help.
"Oxford University's achievement of being ranked the best university in the world for a record nine years is just an unbelievably phenomenal achievement."
Professor Irene Tracey, vice-chancellor of the University of Oxford, added it was a "testament" to everyone at the establishment.
"Above all, I am indebted to all my colleagues at Oxford whose work continues to fire our imaginations, inspire generations, and confront some of the greatest challenges facing our planet," the professor concluded.
